CN207460008U - A kind of circuit for reducing idle loss of switch power supply - Google Patents
A kind of circuit for reducing idle loss of switch power supply Download PDFInfo
- Publication number
- CN207460008U CN207460008U CN201721655310.2U CN201721655310U CN207460008U CN 207460008 U CN207460008 U CN 207460008U CN 201721655310 U CN201721655310 U CN 201721655310U CN 207460008 U CN207460008 U CN 207460008U
- Authority
- CN
- China
- Prior art keywords
- power supply
- feedback control
- circuit
- switching power
- control circuit
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
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Abstract
The utility model is related to a kind of circuits for reducing idle loss of switch power supply.The utility model Switching Power Supply main circuit output connection control chip, control chip output are connected to feedback control circuit, increase a unloaded feedback control circuit in feedback control circuit.The metal-oxide-semiconductor that the utility model is overcome in current Switching Power Supply be lost under no-load condition it is larger, fever it is larger, be easy to cause when serious metal-oxide-semiconductor damage the defects of.The utility model increases a unloaded feedback control circuit in feedback control circuit, reduce the on-off times of Switching Power Supply metal-oxide-semiconductor in unloaded operation, the loss of metal-oxide-semiconductor when significantly reducing switching power circuit unloaded operation, increase the working life of metal-oxide-semiconductor, the whole no-load loss of Switching Power Supply is reduced simultaneously, and application circuit is simple and reliable.
Description
Technical field
The utility model is related to a kind of shape power supply circuit, more particularly to a kind of electricity for reducing idle loss of switch power supply
Road.
Background technology
At present, Switching Power Supply is widely used almost all of electronic equipment with small-sized, light weight and efficient feature, is
Current electronics and information industry develops rapidly a kind of indispensable power mode.
Before the present utility model, larger, fever is lost in the metal-oxide-semiconductor in current Switching Power Supply under no-load condition
It is larger, metal-oxide-semiconductor damage is easy to cause when serious, it is made to be restricted in Switching Power Supply application.
Utility model content
The purpose of this utility model, which is that, overcomes drawbacks described above, provides a kind of electricity for reducing idle loss of switch power supply
Road.
The technical solution of the utility model is：
A kind of circuit for reducing idle loss of switch power supply, Switching Power Supply main circuit output connection control chip, controls core
Piece output is connected to feedback control circuit, is mainly characterized by：Increase a unloaded feedback in feedback control circuit
Control circuit.
The zero load feedback control is provided with a buffer circuit.
The feedback control circuit is in parallel with unloaded feedback control circuit.
The beneficial effects of the utility model are reduced in increasing a unloaded feedback control circuit in feedback control circuit
The on-off times of Switching Power Supply metal-oxide-semiconductor in unloaded operation, metal-oxide-semiconductor when significantly reducing switching power circuit unloaded operation
Loss, increases the working life of metal-oxide-semiconductor, while reduces the whole no-load loss of Switching Power Supply, and application circuit is simple and reliable.
Description of the drawings
Fig. 1 --- switching power circuit no-load loss circuit diagram is reduced in the utility model.
Wherein, Switching Power Supply main circuit 1, control chip 2, feedback control circuit 3, unloaded feedback control circuit 4, (zero load
In feedback control circuit 4) buffer circuit 5.
Specific embodiment：
The utility model is further illustrated with reference to the accompanying drawings and examples：
Switching Power Supply main circuit 1 realizes power conversion.Wherein Q405, Q406, Q407, Q408 are Switching Power Supply metal-oxide-semiconductor, it
By direct current (DC1500V) copped wave of input terminal be ac square wave, then through transformer T404 decompression, rectifier bridge D138 it is whole
Stream, capacitance C149 filtering finally export direct current (DC110V) and power to successive load.Output terminal sets two sampled points, point
It is not output voltage sampled point DCOUT+ and load current sampled point IN.
The IC302 of chip 2 is controlled to control the output of Switching Power Supply main circuit 1 by adjusting driving.Wherein 13 foot OUTD,
14 foot OUTC, 17 foot OUTB, 18 foot OUTA respectively by drive resistance R419, R420, R414, R413 control Q406, Q408,
Q407, Q405's opening and turning off, and then realizes the control of the output to Switching Power Supply main circuit 1.Meanwhile control chip 2
The secondary of the 20 foot FB connection optocouplers U108 of IC302 receives feedback control signal, and FB current potentials are higher, chip output driving duty cycle
Bigger, Switching Power Supply metal-oxide-semiconductor ON time is longer, and Switching Power Supply main circuit output voltage is higher；When FB current potentials are pulled low as 0V
When, chip no longer output driving, Switching Power Supply metal-oxide-semiconductor turns off, and Switching Power Supply main circuit does not work.
Feedback control circuit 3 is by sampling and outputting voltage come the current potential of adjusting control chip FB feet.From main circuit output terminal
Sample reference voltage signals of the obtained output voltage signal DCOUT+ after resistance R354, R307, R352 partial pressure with 2.5V
VREF compares by comparing device U305B, obtains feedback control signal FB1, FB1 by the first of diode D315 access optocouplers U108
Grade realizes the adjusting to controlling chip FB foot current potentials by optocoupler.FB1 current potentials are higher, and FB current potentials are also higher.When output voltage height
When setting value (DC110V), feedback control signal FB1 is lower, and the FB current potentials of optocoupler secondary are also lower, by controlling chip tune
Section driving is so that output voltage reduces, and vice versa.So that the voltage (DC110V) that power supply output is stable.
Unloaded feedback control circuit 4 is by sampling and outputting voltage and load current come the electricity of the FB feet of adjusting control chip 2
Position from the output voltage signal DCOUT+ that main circuit output terminal samples by resistance R34 1, R338, R309 partial pressure after with from
The load current signal IN that main circuit output terminal samples compares by comparing device U308B, is then obtained by buffer circuit
Unloaded feedback control signal FB2, FB2 are realized by optocoupler to controlling core by the primary of diode D316 access optocouplers U108
The adjusting of the FB foot current potentials of piece 2.When FB2 current potentials are 0V (triode Q301 conductings), FB current potentials are also for 0V, at this point, switch is electric
Source metal-oxide-semiconductor shut-off, Switching Power Supply main circuit do not work；When FB2 is hanging (triode Q301 disconnections), FB feet current potential is by anti-at this time
Feedforward control signal FB1 is controlled, i.e., unloaded feedback control circuit 4 does not work.
Feedback control circuit 3 and unloaded feedback control circuit 4 are parallel relationship, the two co- controlling PWM output waveforms.
Buffer circuit 5 is the part in unloaded feedback control circuit 4, Switching Power Supply main circuit during for controlling zero load
Working time.(triode Q301 conductings), i.e. zero load feedback control circuit when unloaded feedback control signal FB2 current potentials are 0V
During effect (Switching Power Supply main circuit does not work, and the working time is reduced), buffer circuit can turn off triode after delay a period of time
Q301 so that unloaded feedback control signal FB2 is hanging, i.e., unloaded feedback control circuit does not work, and (Switching Power Supply main circuit is just
Often work ensures normal output)；Being delayed after a period of time buffer circuit again can turn-on transistor Q301 so that zero load feedback control
Signal FB2 processed is down for 0V, i.e., unloaded feedback control circuit works, and (Switching Power Supply main circuit does not work, and the working time subtracts
It is few).Such process constantly cycles, and reduces working time of the Switching Power Supply main circuit in zero load, and can guarantee switch electricity
The normal output of source main circuit.
Finally, unloaded feedback control circuit 4 reduces the switch of the metal-oxide-semiconductor in unloaded operation of Switching Power Supply main circuit 1
Number reduces the switching loss of metal-oxide-semiconductor, adds the working life of metal-oxide-semiconductor, also reduces the no-load loss of power supply entirety.
Here is unloaded 4 specific workflow of feedback control circuit：
When Switching Power Supply main circuit 1 is operated in light condition, load current sampled signal IN is than output voltage sampling point
Press obtained signal low, i.e. the 6 foot current potentials of comparator U308B are less than 5 foot current potentials so that 7 feet export 12V high level.U308A's
3 feet are 10V by resistance R355 and R308 partial pressures, and 2 feet of U308A are by resistance R368, R329, R301 and R322 partial pressure
The 3 foot current potentials of 1V, i.e. comparator U308A are higher than 2 foot current potentials so that 1 foot exports 12V high level.The high level of 1 foot drives three poles
Pipe Q301 is turned on, and unloaded feedback control signal FB2 is by triode Q301 down for 0V so that U108 grade conducting of optocoupler, so as to
By FB current potentials down for 0V, control chip is exported without driving, and metal-oxide-semiconductor shut-off does not work.
It is charged to capacitance C325 after the 1 foot output 12V high level of U308A so that the 2 foot voltages of U308A constantly raise, when 2
When foot voltage is higher than 3 foot voltage (10V), the 1 foot voltage of U308A becomes 0V, triode Q301 shut-offs, zero load feedback control from 12V
Signal FB2 processed is hanging, and FB feet current potential is controlled by feedback control signal FB1 at this time, controls the normal output driving of chip, metal-oxide-semiconductor is just
Often work ensures that power supply normally exports.
After 1 foot of U308A becomes 0V, the 3 foot voltages of U308A are by partial pressure of connecting again with R355 after R356 and R308 parallel connections
And obtain, it is 5.4V.The voltage of C325 slowly discharges by 10V at this time, i.e. the 2 foot voltages of U308A constantly reduce, when 2 feet
When voltage is less than 3 foot voltage (5.4V), 1 foot of U308A exports 12V high level again, and triode Q301 is turned on again, unloaded anti-
Feedforward control signal FB2 is again by triode Q301 down for 0V so that U108 grade of optocoupler turns on again, and FB current potentials are drawn again
Low, control chip is exported without driving, and metal-oxide-semiconductor shut-off does not work.
In this way, change the 2 foot voltages of U308A using the charge and discharge of capacitance C325, so as to change leading for triode Q301
Logical and shut-off, changes the state of the unloaded feedback control signal FB2 of control, and then realizes the control to FB signals, reduces switch
Working time of the electric power main circuit in zero load, and can guarantee the normal output of Switching Power Supply main circuit.
And when Switching Power Supply is operated in band and carries state, load current sampled signal IN is obtained than output voltage sampling partial pressure
Signal it is high, i.e. the 6 foot current potentials of comparator U308B are higher than 5 foot current potentials so that 7 feet output 0V low levels.The 3 foot voltages of U308A
Less than 2 foot voltages, the 1 foot voltage of U308A is 0V low levels, i.e. triode Q301 is turned off, and unloaded feedback control signal FB2 hangs
Sky, at this time FB feet current potential controlled by feedback control signal FB1, control the normal output driving of chip, metal-oxide-semiconductor normal work, switch
Power supply normally exports.I.e. when Switching Power Supply, which is operated in band, carries state, unloaded feedback control circuit does not work.
Embodiment is sampled using load current compared with output voltage sampling, by the process of capacitor charge and discharge come real
The circuit of Switching Power Supply on-off times in zero load is now reduced, structure, principle are simple, more can clearly react this practicality
New structure, principle and effect.In other Switching Power Supplies that the utility model also can be used for structure similar.
Claims (3)
1. a kind of circuit for reducing idle loss of switch power supply, Switching Power Supply main circuit output connection control chip, control chip
Output is connected to feedback control circuit, it is characterised in that：Increase a unloaded feedback control circuit in feedback control circuit.
2. a kind of circuit for reducing idle loss of switch power supply according to claim 1, it is characterised in that：It is described unloaded anti-
Feedback control is provided with a buffer circuit.
3. a kind of circuit for reducing idle loss of switch power supply according to claim 1, it is characterised in that：The feedback control
Circuit processed is in parallel with unloaded feedback control circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201721655310.2U CN207460008U (en) | 2017-11-29 | 2017-11-29 | A kind of circuit for reducing idle loss of switch power supply |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201721655310.2U CN207460008U (en) | 2017-11-29 | 2017-11-29 | A kind of circuit for reducing idle loss of switch power supply |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN207460008U true CN207460008U (en) | 2018-06-05 |
Family
ID=62275650
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201721655310.2U Expired - Fee Related CN207460008U (en) | 2017-11-29 | 2017-11-29 | A kind of circuit for reducing idle loss of switch power supply |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN207460008U (en) |
-
2017
- 2017-11-29 CN CN201721655310.2U patent/CN207460008U/en not_active Expired - Fee Related
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20180605 Termination date: 20211129 |