CN203193500U - Switching power supply and charging loop thereof - Google Patents

Switching power supply and charging loop thereof Download PDF

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Publication number
CN203193500U
CN203193500U CN 201320210785 CN201320210785U CN203193500U CN 203193500 U CN203193500 U CN 203193500U CN 201320210785 CN201320210785 CN 201320210785 CN 201320210785 U CN201320210785 U CN 201320210785U CN 203193500 U CN203193500 U CN 203193500U
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China
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resistance
power supply
switching power
diode
electric capacity
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CN 201320210785
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Chinese (zh)
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程良意
陈洪涛
严凡
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Gree Electric Appliances Inc of Zhuhai
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Gree Electric Appliances Inc of Zhuhai
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Abstract

The utility model discloses a charging loop of a switching power supply. A first terminal of a first switch tube is connected to a first terminal of a first resistor; a second terminal of the first switch tube is connected to a second terminal of the first resistor; and a control terminal of the first switch tube is connected to a common terminal of a second resistor and a third resistor in an RCD absorption circuit. When power is on, the first resistor restrains a surge current generated the moment the power is on; and after a switching power chip works, voltage difference between the two ends of the second resistor controls the first switch tube to be on so that the first resistor is in a short circuit. In the charging loop of the switching power supply, after the switching power chip works, the first switch tube enables the first resistor to be in a short circuit; since power consumption of semiconductor devices is far less than that of resistors, efficiency of the switching power supply is improved; and meanwhile, since the first resistor is short circuited and heat is no longer generated, environment temperature of the switching power supply is reduced, and the switching power supply is guaranteed to operate stably. The utility model further discloses a switching power supply.

Description

A kind of Switching Power Supply and charge circuit thereof
Technical field
The utility model belongs to the power supply technique field, relates in particular to a kind of Switching Power Supply and charge circuit thereof.
Background technology
Switching Power Supply is to utilize modern power electronics technology, and the time ratio of control switch pipe turn-on and turn-off is to keep a kind of power supply of regulated output voltage.At present, Switching Power Supply is widely used in electronic equipment with small-sized, light weight and high-efficiency characteristics.
Switching Power Supply can produce surge current at powered on moment.In order to guarantee the stable operation of Switching Power Supply, in the current supply circuit of Switching Power Supply, current-limiting resistance is set usually at present, utilize the surge current of current-limiting resistance inhibition powered on moment, as the resistance NTC1 among Fig. 1.
But this current-limiting resistance can consume a large amount of electric energy in the Switching Power Supply running, thereby reduces the efficient of Switching Power Supply, and this current-limiting resistance can produce a large amount of heats simultaneously, and the ambient temperature of the Switching Power Supply that raise is unfavorable for the stable operation of Switching Power Supply.
The utility model content
In view of this, the purpose of this utility model is to provide a kind of charge circuit of Switching Power Supply, can suppress the surge current of powered on moment, improves the efficient of Switching Power Supply simultaneously, and reduces the ambient temperature of Switching Power Supply, guarantees the stable operation of Switching Power Supply.
For achieving the above object, the utility model provides following technical scheme:
A kind of charge circuit of Switching Power Supply, described Switching Power Supply comprises high frequency transformer, described charge circuit comprises rectifier bridge, first switching tube, first resistance, first electric capacity and RCD absorption circuit;
The positive input terminal of described rectifier bridge is connected to first end that the live wire of power supply, zero line, positive output end that negative input end is connected to described power supply be connected to described first resistance, negative output termination with reference to ground, and second end of described first resistance is connected to first end of the elementary winding of described high frequency transformer;
Described RCD absorption circuit comprises second resistance, the 3rd resistance, second electric capacity and first diode, the anode of described first diode is connected to second end of the elementary winding of described high frequency transformer, the negative electrode of described first diode is connected to first end of the elementary winding of described high frequency transformer successively by described the 3rd resistance and second resistance, described second electric capacity is parallel to the two ends of described second resistance and the 3rd resistance;
First end of described first switching tube is connected to first end of described first resistance, and second end of described first switching tube is connected to second end of described first resistance, and described first control end of switching tube is connected to the common port of described second resistance and the 3rd resistance;
First end of described first electric capacity is connected to second end of described first resistance, and second end of described first electric capacity is connected to the negative output terminal of described rectifier bridge.
Preferably, in the charge circuit of above-mentioned Switching Power Supply, the resistance of described second resistance is less than the resistance of described the 3rd resistance.
Preferably, in the charge circuit of above-mentioned Switching Power Supply, the ratio of the resistance of described second resistance and the 3rd resistance is between 1:20 to 1:10.
Preferably, the charge circuit of above-mentioned Switching Power Supply also comprises voltage stabilizing didoe, and second end, negative electrode that described voltage stabilizing didoe anode is connected to described first switching tube are connected to described first control end of switching tube.
Preferably, in the charge circuit of above-mentioned Switching Power Supply, described RCD absorption circuit also comprises Transient Suppression Diode, and common port, the negative electrode that the anode of described Transient Suppression Diode is connected to described second electric capacity and described second resistance is connected to the negative electrode of described first diode.
Preferably, in the charge circuit of above-mentioned Switching Power Supply, described first switching tube is triode, field effect transistor or one-way SCR.
The invention also discloses a kind of charge circuit of Switching Power Supply, described Switching Power Supply comprises high frequency transformer, and described charge circuit comprises half-wave rectifying circuit, first switching tube, first resistance, first electric capacity and RCD absorption circuit;
Described half-wave rectifying circuit comprises second diode, the anode of described second diode is connected to the live wire of power supply, the negative electrode of described second diode is connected to first end of described first resistance, and second end of described first resistance is connected to first end of the elementary winding of described high frequency transformer;
Described RCD absorption circuit comprises second resistance, the 3rd resistance, second electric capacity and first diode, the anode of described first diode is connected to second end of the elementary winding of described high frequency transformer, the negative electrode of described first diode is connected to first end of the elementary winding of described high frequency transformer successively by described the 3rd resistance and second resistance, described second electric capacity is parallel to the two ends of described second resistance and the 3rd resistance;
First end of described first switching tube is connected to first end of described first resistance, and second end of described first switching tube is connected to second end of described first resistance, and described first control end of switching tube is connected to the common port of described second resistance and the 3rd resistance;
First end of described first electric capacity is connected to second end of described first resistance, and second end of described first electric capacity is connected to the zero line of described power supply.
Preferably, in the charge circuit of above-mentioned Switching Power Supply, described RCD absorption circuit also comprises Transient Suppression Diode, and common port, the negative electrode that the anode of described Transient Suppression Diode is connected to described second electric capacity and described second resistance is connected to the negative electrode of described first diode.
On the other hand, the utility model discloses a kind of Switching Power Supply, comprise switching power source chip, second switch pipe, high frequency transformer, and above-mentioned any charge circuit; First end of described second switch pipe is connected to second end of the elementary winding of described high frequency transformer, second termination of described second switch pipe is with reference to ground, the control end of described second switch pipe is connected to the control signal output of described switching power source chip, and first end of first electric capacity in the described charge circuit is connected to the feeder ear of described switching power source chip.
Preferably, also comprise current sense resistor in above-mentioned Switching Power Supply, described current sense resistor is connected second end of described second switch pipe and described with reference between the ground; The common port of described current sense resistor and described second switch pipe is connected to the signals collecting end of described switching power source chip.
This shows, the beneficial effects of the utility model are: the current supply circuit of the disclosed Switching Power Supply of the utility model, at the two ends of first resistance first switching tube in parallel, when powering on, first resistance can suppress the surge current of powered on moment, after switching power source chip work, the first switching tube conducting is with first resistive short, first resistance consumed power no longer afterwards, and the power consumption of semiconductor device is much smaller than the power consumption of resistance, so current supply circuit of the disclosed Switching Power Supply of the utility model, improved the efficient of Switching Power Supply, because first resistance is no longer produced heat by short circuit, therefore relative prior art has reduced the ambient temperature of Switching Power Supply, has guaranteed the stable operation of Switching Power Supply simultaneously.
Description of drawings
In order to be illustrated more clearly in the utility model embodiment or technical scheme of the prior art, to do to introduce simply to the accompanying drawing of required use in embodiment or the description of the Prior Art below, apparently, accompanying drawing in describing below is embodiment more of the present utility model, for those of ordinary skills, under the prerequisite of not paying creative work, can also obtain other accompanying drawing according to these accompanying drawings.
Fig. 1 is the structural representation of the charge circuit of existing Switching Power Supply;
Fig. 2 is the structural representation of the charge circuit of the disclosed a kind of Switching Power Supply of the utility model;
Fig. 3 is the structural representation of the charge circuit of the disclosed another kind of Switching Power Supply of the utility model;
Fig. 4 is the structural representation of the disclosed a kind of Switching Power Supply of the utility model;
Fig. 5 is the structural representation of the disclosed another kind of Switching Power Supply of this practical information.
Embodiment
For the purpose, technical scheme and the advantage that make the utility model embodiment clearer, below in conjunction with the accompanying drawing among the utility model embodiment, technical scheme among the utility model embodiment is clearly and completely described, obviously, described embodiment is the utility model part embodiment, rather than whole embodiment.Based on the embodiment in the utility model, those of ordinary skills are not making the every other embodiment that obtains under the creative work prerequisite, all belong to the scope of the utility model protection.
The utility model discloses a kind of charge circuit of Switching Power Supply, can suppress the surge current of powered on moment, improve the efficient of Switching Power Supply simultaneously, and reduce the ambient temperature of Switching Power Supply, guarantee the stable operation of Switching Power Supply.
Referring to Fig. 2, Fig. 2 is the structural representation of the charge circuit of the disclosed a kind of Switching Power Supply of the utility model.This charge circuit comprises rectifier bridge, the first switching tube Q1, first resistance R 1, first capacitor C 1 and RCD absorption circuit.
Wherein:
Rectifier bridge comprises the second diode D2, the 3rd diode D3, the 4th diode D4 and the 5th diode D5, and the alternating current that is used for power supply is provided is converted to direct current.The positive input terminal of rectifier bridge is connected to the live wire L of power supply, the negative input end of rectifier bridge is connected to the zero line N of power supply, the positive output end of rectifier bridge is connected to first end of first resistance R 1, the negative output termination of rectifier bridge is with reference to ground, and second end of first resistance R 1 is connected to first end of the elementary winding of Switching Power Supply medium-high frequency transformer T1.
The RCD absorption circuit comprises second resistance R 2, the 3rd resistance R 3, second capacitor C 2 and the first diode D1.The anode of the first diode D1 is connected to second end of the elementary winding of high frequency transformer T1, the negative electrode of the first diode D1 is connected to first end of the elementary winding of high frequency transformer T1 successively by the 3rd resistance R 3 and second resistance R 2, second capacitor C 2 is parallel to the two ends of second resistance R 2 and the 3rd resistance R 3.First end of the first switching tube Q1 is connected to first end of first resistance R 1, and second end of the first switching tube Q1 is connected to second end of first resistance R 1, and the control end of the first switching tube Q1 is connected to the common port of second resistance R 2 and the 3rd resistance R 3.
First end of second switch pipe Q2 in the Switching Power Supply is connected with second end of the elementary winding of high frequency transformer T1, at second switch pipe Q2 shutdown moment, the elementary winding of high frequency transformer T1 produces reflected voltage, and this reflected voltage makes the anode place of the diode D1 that wins produce higher electric energy.The RCD circuit can reduce the voltage of first end of second switch pipe Q2 in the Switching Power Supply, and Q2 is not breakdown for protection second switch pipe.Concrete; at second switch pipe Q2 shutdown moment; the electric energy that the anode place of the first diode D1 generates makes the diode D1 conducting of winning; thereby second capacitor C 2 is charged; second capacitor C 2 is discharged through second resistance R 2 and the 3rd resistance R 3 afterwards; so that the energy when absorbing next switch motion, Q2 is not breakdown for protection second switch pipe.
In addition, have no progeny in second switch pipe Q2 pass, the reflected voltage that 3 couples of high frequency transformer T1 of second resistance R 2 in the RCD circuit and the 3rd resistance R produce carries out dividing potential drop, and the voltage difference at second resistance R, 2 two ends forms the required bias voltage of the first switching tube Q1 conducting.In the enforcement, the resistance of second resistance R 2 can be set less than the resistance of the 3rd resistance R 3, so that the voltage difference at second resistance R, 2 two ends is less, avoid damaging the first switching tube Q1.Preferably, the ratio of the resistance of second resistance R 2 and the 3rd resistance R 3 is between the 1:20 to 1:10.
First end of first capacitor C 1 is connected to second end of first resistance R 1, and second end of first capacitor C 1 is connected to the negative output terminal of rectifier bridge, and first capacitor C 1 is used to switching power source chip 2 power supplies in the Switching Power Supply.
Running to the charge circuit of Switching Power Supply shown in Figure 2 describes below:
When powering on, power supply gives first capacitor C 1 charging through first resistance R 1, the first not conducting of switching tube Q1 this moment, and this first resistance R 1 is as current-limiting resistance.
When the voltage of first capacitor C, 1 first end reaches amplitude and specific, switching power source chip 2 in the Switching Power Supply is started working, second switch pipe Q2 conducting, the elementary winding of high frequency transformer T1 has electric current to flow through, the electric current of this variation induces the magnetic field energy of variation, and energy is stored among the high frequency transformer T1.Second switch pipe Q2 closes and has no progeny, and this energy is passed to the secondary winding of high frequency transformer T1, makes secondary winding have electric current to flow through, and this electric current induces magnetic field energy, produces reflected voltage at the two ends of elementary winding.This reflected voltage makes the voltage at the negative electrode place of the diode D1 that wins be higher than the voltage at the second end place of first resistance R 1, just the voltage of the control end of the first switching tube Q1 is higher than the voltage of second end, first switching tube Q1 conducting this moment, with first resistance R, 1 short circuit, make the no longer consumed power of resistance R 1 of winning.
The current supply circuit of the above-mentioned disclosed Switching Power Supply of the utility model, at the two ends of the first resistance R 1 first switching tube Q1 in parallel, when powering on, first resistance R 1 can suppress the surge current of powered on moment, after switching power source chip 2 work, the first switching tube Q1 conducting is with 1 short circuit of first resistance R, first resistance R 1 is consumed power no longer, and the power consumption of semiconductor device is much smaller than the power consumption of resistance, therefore the current supply circuit of the disclosed Switching Power Supply of the utility model has improved the efficient of Switching Power Supply, simultaneously because first resistance R 1 is no longer produced heat after the short circuit, therefore relative prior art has reduced the ambient temperature of Switching Power Supply, has guaranteed the stable operation of Switching Power Supply.
In the enforcement, in the current supply circuit of Switching Power Supply shown in Figure 2, voltage stabilizing didoe ZD1 can be set further.Second end, the negative electrode that the anode of this voltage stabilizing didoe ZD1 is connected to the first switching tube Q1 is connected to the control end of the first switching tube Q1.Voltage stabilizing didoe ZD1 is used for preventing abnormal conditions makes second end of the first switching tube Q1 and the overtension between the control end, thereby prevents that the first switching tube Q1 is damaged.
The invention also discloses a kind of charge circuit of Switching Power Supply, see also Fig. 3, Fig. 3 is the structural representation of the charge circuit of the disclosed another kind of Switching Power Supply of the utility model.This charge circuit comprises half-wave rectifying circuit, the first switching tube Q1, first resistance R 1, first capacitor C 1 and RCD absorption circuit.
Wherein:
Half-wave rectifying circuit comprises the second diode D2, live wire L, the negative electrode that the anode of the second diode D2 is connected to power supply is connected to first end of first resistance R 1, and second end of first resistance R 1 is connected to first end of the elementary winding of Switching Power Supply medium-high frequency transformer T1.
The RCD absorption circuit comprises second resistance R 2, the 3rd resistance R 3, second capacitor C 2 and the first diode D1.The anode of the first diode D1 is connected to second end of the elementary winding of high frequency transformer T1, the negative electrode of the first diode D1 is connected to first end of the elementary winding of high frequency transformer T1 successively by the 3rd resistance R 3 and second resistance R 2, second capacitor C 2 is parallel to the two ends of second resistance R 2 and the 3rd resistance R 3.First end of the first switching tube Q1 is connected to first end of first resistance R 1, and second end of the first switching tube Q1 is connected to second end of first resistance R 1, and the control end of the first switching tube Q1 is connected to the common port of second resistance R 2 and the 3rd resistance R 3.
First end of second switch pipe Q2 in the Switching Power Supply is connected with second end of the elementary winding of high frequency transformer T1, at second switch pipe Q2 shutdown moment, the elementary winding of high frequency transformer T1 produces reflected voltage, and this reflected voltage makes the anode place of the diode D1 that wins produce higher electric energy.The RCD circuit can reduce the voltage of first end of second switch pipe Q2 in the Switching Power Supply, and Q2 is not breakdown for protection second switch pipe.Concrete; at second switch pipe Q2 shutdown moment; the electric energy that the anode place of the first diode D1 generates makes the diode D1 conducting of winning; thereby second capacitor C 2 is charged; second capacitor C 2 is discharged through second resistance R 2 and the 3rd resistance R 3 afterwards; so that the energy when absorbing next switch motion, Q2 is not breakdown for protection second switch pipe.
In addition, have no progeny in second switch pipe Q2 pass, the reflected voltage that 3 couples of high frequency transformer T1 of second resistance R 2 in the RCD circuit and the 3rd resistance R produce carries out dividing potential drop, and the voltage difference at second resistance R, 2 two ends forms the required bias voltage of the first switching tube Q1 conducting.In the enforcement, the resistance of second resistance R 2 can be set less than the resistance of the 3rd resistance R 3, so that the voltage difference at second resistance R, 2 two ends is less, avoid damaging the first switching tube Q1.Preferably, the ratio of the resistance of second resistance R 2 and the 3rd resistance R 3 is between the 1:20 to 1:10.
First end of first capacitor C 1 is connected to second end of first resistance R 1, and second end of first capacitor C 1 is connected to the zero line N of power supply, and first capacitor C 1 is used to switching power source chip 2 power supplies in the Switching Power Supply.
The charge circuit of Switching Power Supply shown in Figure 3 is compared with the charge circuit of Switching Power Supply shown in Figure 2, and difference is to adopt half-wave rectifying circuit, and the charge circuit of Switching Power Supply shown in Figure 3 is only in the positive half cycle work of alternating current.The running of the running of the charge circuit of Switching Power Supply shown in Figure 3 and the charge circuit of Switching Power Supply shown in Figure 2 is similar, sees also preamble and describes, and does not repeat them here.
The current supply circuit of the Switching Power Supply that the utility model is shown in Figure 3, at the two ends of the first resistance R 1 first switching tube Q1 in parallel, when powering on, first resistance R 1 can suppress the surge current of powered on moment, after switching power source chip 2 work, the first switching tube Q1 conducting is with 1 short circuit of first resistance R, first resistance R 1 is consumed power no longer, and the power consumption of semiconductor device is much smaller than the power consumption of resistance, so current supply circuit of the disclosed Switching Power Supply of the utility model Fig. 3, improved the efficient of Switching Power Supply, simultaneously because first resistance R 1 is no longer produced heat after the short circuit, therefore relative prior art has reduced the ambient temperature of Switching Power Supply, has guaranteed the stable operation of Switching Power Supply.
In the enforcement, in the current supply circuit of Switching Power Supply shown in Figure 3, voltage stabilizing didoe ZD1 can be set further.Second end, the negative electrode that the anode of this voltage stabilizing didoe ZD1 is connected to the first switching tube Q1 is connected to the control end of the first switching tube Q1.Voltage stabilizing didoe ZD1 is used for preventing abnormal conditions makes second end of the first switching tube Q1 and the overtension between the control end, thereby prevents that the first switching tube Q1 is damaged.
In addition, the structure of the absorption of the RCD among above-mentioned disclosed each embodiment of the utility model circuit also is not limited to Fig. 2 and structure shown in Figure 3.On the basis of Fig. 2 and RCD absorption circuit shown in Figure 3, Transient Suppression Diode can further be set, be also referred to as the TVS diode, common port, the negative electrode that the anode of this Transient Suppression Diode is connected to second capacitor C 2 and second resistance R 2 is connected to the negative electrode of the first diode D1.
Second switch pipe Q2 shutdown moment in Switching Power Supply; the anode of the first diode D1 produces higher electric energy; this moment, the two poles of the earth of this TVS diode were subjected to reverse transient state high energy impact events; its working impedance can be down to very low conduction value immediately; absorb the surge power up to thousands of watts simultaneously; make the voltage clamp of two interpolars in safety value, protection second switch pipe Q2 is not damaged.
In the charge circuit of above-mentioned disclosed each Switching Power Supply of the utility model, the first switching tube Q1 can be triode, field effect transistor or one-way SCR.When the first switching tube Q1 was triode, first end was collector electrode, and second end is emitter, and control end is base stage; When the first switching tube Q1 was field effect transistor, first end was drain electrode, and second end is source electrode, and control end is grid; When the first switching tube Q1 was one-way SCR, first end was anode, and second end is negative electrode, and control end is gate pole.
Because the cost of triode is lower, therefore the first switching tube Q1 preferably adopts triode, to reduce the cost of charge circuit.
The utility model also discloses a kind of Switching Power Supply, and this Switching Power Supply comprises switching power source chip, second switch pipe, high frequency transformer, and charge circuit.Wherein, charge circuit can be above-mentioned disclosed any one charge circuit of the utility model, first end of second switch pipe is connected to second end of the elementary winding of high frequency transformer, second termination of second switch pipe is with reference to ground, the control end of second switch pipe is connected to the control signal output of switching power source chip, and first end of first electric capacity in the charge circuit is connected to the feeder ear of switching power source chip.Describe below in conjunction with Fig. 4.
Referring to Fig. 4, Fig. 4 is the structural representation of the disclosed a kind of Switching Power Supply of the utility model,
This Switching Power Supply comprises switching power source chip 2, second switch pipe Q2, high frequency transformer T1, and charge circuit.The structure of this charge circuit is consistent with the structure of the charge circuit shown in the accompanying drawing 2, sees also the preamble associated description, does not repeat them here.
First end of second switch pipe Q2 is connected to second end of the elementary winding of high frequency transformer T1, second termination of second switch pipe Q2 is with reference to ground, the control end of second switch pipe Q2 is connected to the control signal output of switching power source chip 2, and first end of first capacitor C 1 is connected to the feeder ear of switching power source chip 2.
Wherein, second switch pipe Q2 can be power field effect pipe MOSFET, also can be insulated gate bipolar transistor IGBT.When second switch pipe Q2 was MOSFET, first end was drain electrode, and second end is source electrode, and control end is grid; When second switch pipe Q2 was IGBT, first end was collector electrode, and second end is emitter, and control end is gate pole.
The disclosed Switching Power Supply of the utility model, at the two ends of first resistance first switching tube in parallel, when powering on, first resistance can suppress the surge current of powered on moment, after switching power source chip work, the first switching tube conducting is with first resistive short, first resistance is consumed power no longer, and the power consumption of semiconductor device is much smaller than the power consumption of resistance, therefore the disclosed Switching Power Supply of the utility model has higher efficient, because first resistance is no longer produced heat by short circuit, therefore relative prior art has reduced the ambient temperature of Switching Power Supply, has guaranteed the stable operation of Switching Power Supply simultaneously.
Referring to Fig. 5, Fig. 5 is the structural representation of the disclosed another kind of Switching Power Supply of the utility model.
This Switching Power Supply comprises switching power source chip 2, second switch pipe Q2, high frequency transformer T1, current sense resistor R4, and charge circuit.The structure of this charge circuit is consistent with the structure of the charge circuit shown in the accompanying drawing 2, sees also the preamble associated description, does not repeat them here.Compare with Switching Power Supply shown in Figure 4, further increase current sense resistor R4, simultaneously switching power source chip 2 signalization collection terminals.
First end of second switch pipe Q2 is connected to second end of the elementary winding of high frequency transformer T1, second end of second switch pipe Q2 connects with reference to ground by current sense resistor R4, the control end of second switch pipe Q2 is connected to the control signal output of switching power source chip 2, the common port of current sense resistor R4 and second switch pipe Q2 is connected to the signals collecting end of switching power source chip 2, and first end of first capacitor C 1 is connected to the feeder ear of switching power source chip 2.
Each example adopts the mode of going forward one by one to describe in this specification, and what each example stressed is and the difference of other embodiment that identical similar part is mutually referring to getting final product between each example.
To the above-mentioned explanation of the disclosed embodiments, make this area professional and technical personnel can realize or use the utility model.Multiple modification to these embodiment will be apparent concerning those skilled in the art, and defined General Principle can realize under the situation that does not break away from spirit or scope of the present utility model in other embodiments herein.Therefore, the utility model will can not be restricted to these embodiment shown in this article, but will meet the wideest scope consistent with principle disclosed herein and features of novelty.

Claims (10)

1. the charge circuit of a Switching Power Supply, described Switching Power Supply comprises high frequency transformer, it is characterized in that, described charge circuit comprises rectifier bridge, first switching tube, first resistance, first electric capacity and RCD absorption circuit;
The positive input terminal of described rectifier bridge is connected to first end that the live wire of power supply, zero line, positive output end that negative input end is connected to described power supply be connected to described first resistance, negative output termination with reference to ground, and second end of described first resistance is connected to first end of the elementary winding of described high frequency transformer;
Described RCD absorption circuit comprises second resistance, the 3rd resistance, second electric capacity and first diode, the anode of described first diode is connected to second end of the elementary winding of described high frequency transformer, the negative electrode of described first diode is connected to first end of the elementary winding of described high frequency transformer successively by described the 3rd resistance and second resistance, described second electric capacity is parallel to the two ends of described second resistance and the 3rd resistance;
First end of described first switching tube is connected to first end of described first resistance, and second end of described first switching tube is connected to second end of described first resistance, and described first control end of switching tube is connected to the common port of described second resistance and the 3rd resistance;
First end of described first electric capacity is connected to second end of described first resistance, and second end of described first electric capacity is connected to the negative output terminal of described rectifier bridge.
2. the charge circuit of Switching Power Supply according to claim 1 is characterized in that, the resistance of described second resistance is less than the resistance of described the 3rd resistance.
3. the charge circuit of Switching Power Supply according to claim 2 is characterized in that, the ratio of the resistance of described second resistance and described the 3rd resistance is between 1:20 to 1:10.
4. the charge circuit of Switching Power Supply according to claim 1 is characterized in that, also comprises voltage stabilizing didoe, and second end, negative electrode that described voltage stabilizing didoe anode is connected to described first switching tube are connected to described first control end of switching tube.
5. according to the charge circuit of each described Switching Power Supply in the claim 1 to 4, it is characterized in that, described RCD absorption circuit also comprises Transient Suppression Diode, and common port, the negative electrode that the anode of described Transient Suppression Diode is connected to described second electric capacity and described second resistance is connected to the negative electrode of described first diode.
6. according to the charge circuit of each described Switching Power Supply in the claim 1 to 4, it is characterized in that described first switching tube is triode, field effect transistor or one-way SCR.
7. the charge circuit of a Switching Power Supply, described Switching Power Supply comprises high frequency transformer, it is characterized in that, described charge circuit comprises half-wave rectifying circuit, first switching tube, first resistance, first electric capacity and RCD absorption circuit;
Described half-wave rectifying circuit comprises second diode, the anode of described second diode is connected to the live wire of power supply, the negative electrode of described second diode is connected to first end of described first resistance, and second end of described first resistance is connected to first end of the elementary winding of described high frequency transformer;
Described RCD absorption circuit comprises second resistance, the 3rd resistance, second electric capacity and first diode, the anode of described first diode is connected to second end of the elementary winding of described high frequency transformer, the negative electrode of described first diode is connected to first end of the elementary winding of described high frequency transformer successively by described the 3rd resistance and second resistance, described second electric capacity is parallel to the two ends of described second resistance and the 3rd resistance;
First end of described first switching tube is connected to first end of described first resistance, and second end of described first switching tube is connected to second end of described first resistance, and described first control end of switching tube is connected to the common port of described second resistance and the 3rd resistance;
First end of described first electric capacity is connected to second end of described first resistance, and second end of described first electric capacity is connected to the zero line of described power supply.
8. the charge circuit of Switching Power Supply according to claim 7, it is characterized in that, described RCD absorption circuit also comprises Transient Suppression Diode, and common port, the negative electrode that the anode of described Transient Suppression Diode is connected to described second electric capacity and described second resistance is connected to the negative electrode of described first diode.
9. a Switching Power Supply is characterized in that, comprises switching power source chip, second switch pipe, high frequency transformer, and as each described charge circuit in the claim 1 to 8;
First end of described second switch pipe is connected to second end of the elementary winding of described high frequency transformer, second termination of described second switch pipe is with reference to ground, the control end of described second switch pipe is connected to the control signal output of described switching power source chip, and first end of first electric capacity in the described charge circuit is connected to the feeder ear of described switching power source chip.
10. Switching Power Supply according to claim 9 is characterized in that, also comprises current sense resistor, and described current sense resistor is connected second end of described second switch pipe and described with reference between the ground; The common port of described current sense resistor and described second switch pipe is connected to the signals collecting end of described switching power source chip.
CN 201320210785 2013-04-23 2013-04-23 Switching power supply and charging loop thereof Expired - Fee Related CN203193500U (en)

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103986147A (en) * 2014-05-27 2014-08-13 深圳市中兴移动通信有限公司 Power supply and switching tube protection circuit thereof
CN105262332A (en) * 2015-11-18 2016-01-20 广东工业大学 Power-on surge current suppression circuit applied to switching power supply
CN106571737A (en) * 2015-10-12 2017-04-19 珠海格力电器股份有限公司 Surge current eliminating circuit of switching power supply, and switching power supply
CN108803370A (en) * 2018-08-01 2018-11-13 合肥阅辞科技有限公司 Intelligent home control system

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103986147A (en) * 2014-05-27 2014-08-13 深圳市中兴移动通信有限公司 Power supply and switching tube protection circuit thereof
CN106571737A (en) * 2015-10-12 2017-04-19 珠海格力电器股份有限公司 Surge current eliminating circuit of switching power supply, and switching power supply
CN105262332A (en) * 2015-11-18 2016-01-20 广东工业大学 Power-on surge current suppression circuit applied to switching power supply
CN108803370A (en) * 2018-08-01 2018-11-13 合肥阅辞科技有限公司 Intelligent home control system

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