CN1592019A - Power supply overvoltage protecting method and power circuit thereof - Google Patents
Power supply overvoltage protecting method and power circuit thereof Download PDFInfo
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- CN1592019A CN1592019A CN 03155472 CN03155472A CN1592019A CN 1592019 A CN1592019 A CN 1592019A CN 03155472 CN03155472 CN 03155472 CN 03155472 A CN03155472 A CN 03155472A CN 1592019 A CN1592019 A CN 1592019A
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Abstract
This invention discloses a protection method for power supply over voltage, in which, the supply circuit composed of supply modules provides voltage to load by detecting the output voltage of the supply module and generating over voltage signals when over voltage appears, feeding back the overvoltage signal to the said supply circuit, so that the supply circuit stops providing power to the load. The invention also discloses a supply circuit.
Description
Technical field
The present invention relates to power technology, particularly a kind of guard method of power supply overvoltage and power circuit thereof.
Background technology
The protective circuit of general power module all in the inner realization of power supply, seldom increases power module output overvoltage breaking circuit.Because the over-voltage protection point of power module itself is generally 120%～140% of output voltage, far surpassed the voltage range that most load devices allow.When the power module output voltage raises but also do not arrive the over-voltage protection point of module itself, be easy to cause the damage of supported chip.
Summary of the invention
The object of the present invention is to provide a kind of guard method and power circuit of overvoltage of power supply, to solve the problem that causes load to damage easily because of the power supply overvoltage in the prior art.
Realize technical scheme of the present invention:
A kind of guard method of overvoltage of power supply, this method can provide power supply to load by the power circuit of being made up of power module, and described method comprises step:
Output voltage to power module carries out the overvoltage detection, and produces the overvoltage signal when overvoltage occurring;
To described power circuit, make this power circuit stop to power to the load described overvoltage signal feedback.
Wherein:
The over-voltage protection method of power module makes the test point signal remain on overvoltage condition after detecting overvoltage.
Described overvoltage signal feeds back in the power circuit by coupled modes.
A kind of power circuit comprises power module, and its design feature is also to comprise:
Mains switch is used to control the input power supply of power module or/and out-put supply;
Testing circuit, its input is connected with the power output end of described power module; Be used to detect overvoltage;
Control circuit, its input is connected with the output of described testing circuit, and its output is connected with described mains switch; This control circuit is according to the detection signal control mains switch of testing circuit output.
A kind of power circuit comprises power module, it is characterized in that also comprising:
Testing circuit, its input is connected with the power output end of described power module; Be used to detect overvoltage;
Control circuit, its input is connected with the output of described testing circuit, and its output is connected with the control end of described power module; This control circuit is according to the voltage output of the detection signal control power module of testing circuit output.
Wherein:
Described power circuit also comprises: regenerative circuit, and its input is connected with input with the output of described testing circuit respectively with output; Be used for when testing circuit output overvoltage signal the signal of the input of this testing circuit is maintained overvoltage condition.
The present invention has following beneficial effect:
1, at the peripheral overvoltage crowbar that increases of power module, can reach the high accuracy overvoltage protection by the precision of selecting detection means.
2, the power supply output overvoltage closes and has no progeny, and switching signal is guaranteed the power supply reliable turn-off by controlling the detection clamping that regenerative circuit can make the power supply detection chip.
3, can adjust according to demand for over-voltage protection point.
4, adopt the coupled modes isolation signals, avoided of the influence of power module control end internal driving, draw high or drag down to the voltage reliability of assurance power control terminal commutation circuit.
Description of drawings
Fig. 1, Fig. 2 and Fig. 3 are theory diagram of the present invention;
Fig. 4 is the circuit theory diagrams of Fig. 1;
Fig. 5 is the circuit theory diagrams of Fig. 2;
Fig. 6 is the circuit theory diagrams of Fig. 3.
Embodiment
Consult shown in Figure 1ly, power circuit comprises power module, testing circuit, regenerative circuit and control circuit.The input of testing circuit is connected with the power output end of power module, and the input of regenerative circuit is connected with input with the output of described testing circuit respectively with output; The input of control circuit is connected with the output of testing circuit, and its output is connected with the control end of power module.Consult shown in Figure 2ly, power circuit comprises power module, mains switch SW1, testing circuit, regenerative circuit and control circuit.Mains switch SW1 is connected in the input mains side of power module, and the output of control circuit is connected with mains switch SW1; All the other connections are identical with Fig. 1.Consult shown in Figure 3ly, mains switch is connected in the out-put supply side of power module, and annexation is identical with Fig. 2.
After power module powered on, testing circuit carried out the overvoltage detection to the output voltage of power module, and output overvoltage signal when detecting the output voltage overvoltage makes testing circuit input (test point) signal keep overvoltage condition by regenerative circuit simultaneously; The overvoltage signal that control circuit is exported according to testing circuit is controlled control end CNT, mains switch SW1 or the mains switch SW2 of power module, the output that comes power cutoff.
Describe respectively below in conjunction with circuit theory diagrams:
Consult shown in Figure 4ly, the control end CNT by the control power module realizes control is turn-offed in the overvoltage of power module.With control end CNT is that negative logic is controlled to be example (as long as power module of positive logic control is with the control level of control end CNT oppositely).
When the power module of negative logic control was low at the CNT level, power supply output was normal.Whether normal, detect and provide alarm signal to power supply output overvoltage situation if detecting the output of secondary power supply module, avoid overvoltage for the protection load and damage, and changes the level of the control end CNT of power module by the conducting of control light lotus root, thus power cutoff output.
Testing circuit comprises resistance R 3, resistance R 4, capacitor C 1, comparator U1.Regenerative circuit is made up of resistance R 1, capacitor C 3 and optocoupler N1.Control circuit is made up of resistance (R2, R5, R6, R7, R8), optocoupler N2, capacitor C 2 and voltage stabilizing didoe (D1).
The change of test point after the overvoltage of power module output voltage, optocoupler N1 conducting in the regenerative circuit when detecting overvoltage, thus the overvoltage signal of test point is maintained high level state always, promptly realize the overvoltage locking function by positive feedback.For avoiding the impedance influences of power module control end, in control circuit, adopt voltage stabilizing didoe to stablize the A point voltage, as the A point voltage is stabilized in 18V, no matter how the internal driving of the control end of power module influences, can guarantee that all pressure reduction is 18V between the AB like this.Guarantee like this that at light lotus root N2 the control end CNT of power module is in low level by resistance R 6, R8 dividing potential drop not under the situation of conducting, power module output is normal.When light lotus root N2 conducting, then by resistance R 5, R7, R8 dividing potential drop, the control end CNT of power module drawn high to be in high level, power module turn-offs no-output.Also can satisfy simultaneously-36V～-the 72V wide input range in, the resistance R 7 of selection, R8 resistance are unlikely low excessively, cause the electric current that flows through the light lotus root excessive, selective light lotus root device difficulty.
The concrete course of work is as follows: the power supply output overvoltage is detected by after resistance R 3, the R4 dividing potential drop, and level is sent into comparator U1; Export just often when power module, comparator is exported high level, not conducting of light lotus root N2, and by resistance R 6, R8 dividing potential drop, the CNT of power module end is low level between the AB, power module is exported normally.Export when too high when voltage, the power supply test point is a high level, and comparator produces the U1 output low level, but report and alarm is controlled light lotus root N2 conducting simultaneously, and the control end CNT logic level of power module is drawn high by resistance R 5, R7, R8 dividing potential drop, and power module is turned off.The low level signal control light lotus root N1 conducting of comparator output simultaneously is locked in the power supply test point on the high level.So far, module is lockable, and reaches the purpose of protection.
Consult Fig. 5, realize control is turn-offed in the overvoltage of power module with the mains switch of control power module input.The mains switch SW1 conducting of power module input, power supply output is normal.Whether normal, detect and provide alarm signal to power supply output overvoltage situation if detecting the output of secondary power supply module, avoid overvoltage for the protection load and damage, and comes power cutoff switch SW 1 by the conducting of controlling the light lotus root, thereby cut off the output of input power supply power cutoff.
Testing circuit comprises resistance R 3, resistance R 4, capacitor C 1, comparator U1.Regenerative circuit is made up of resistance R 1, capacitor C 3 and optocoupler N1.Control circuit is by resistance (R2, R5, R6), optocoupler N2, capacitor C 2 and voltage stabilizing didoe D1, and mains switch is metal-oxide-semiconductor SW1.Wherein voltage stabilizing didoe D1 is used to protect metal-oxide-semiconductor.
The concrete course of work is as follows: the power supply output overvoltage is detected by after resistance R 3, the R4 dividing potential drop, and level is sent into comparator U1.Export just often when power module, comparator is exported high level, and not conducting of light lotus root N2 by resistance R 5, R6 dividing potential drop, guarantees metal-oxide-semiconductor SW1 conducting, and power module output is normal.Export when too high when voltage, the power supply test point is a high level, and comparator output low level, but report and alarm are controlled light lotus root N2 conducting simultaneously, and resistance R 6 is by short circuit, and the G utmost point of metal-oxide-semiconductor drags down, and SW1 disconnects, and power module is turned off.The low level signal control light lotus root N1 conducting of comparator output simultaneously is locked in the power supply test point on the high level.So far, module is lockable, and reaches the purpose of protection.
Consult Fig. 6, control is turn-offed in the overvoltage of power module with the mains switch SW2 realization of control power module outlet.Switch SW 2 conductings of power module outlet, power supply output is normal.Whether normal, detect and provide alarm signal to power supply output overvoltage situation if detecting the output of secondary power supply module, avoid overvoltage for the protection load and damage, and turn-offs SW2 by the conducting of control light lotus root, cuts off the out-put supply circuit.
Testing circuit comprises resistance R 3, resistance R 4, capacitor C 1, comparator U1.Regenerative circuit is made up of resistance R 1, capacitor C 3 and optocoupler N1.Control circuit comprises resistance R 2 and voltage stabilizing didoe D1.Mains switch SW2 is a metal-oxide-semiconductor, adopts the metal-oxide-semiconductor of P raceway groove.
The concrete course of work is as follows: the power supply output overvoltage is detected by after resistance R 3, the R4 dividing potential drop, and level is sent into comparator.When power module is exported just often comparator output low level, mains switch SW2 conducting.Export when too high when voltage, the power supply test point is a high level, comparator output high level, but report and alarm simultaneously by drawing on the resistance R 2, makes the G utmost point of mains switch SW2 identical with S utmost point level, power supply switch tube SW2 shutoff, the outlet line of cutting off the electricity supply.The low level signal control light lotus root N1 conducting of comparator output simultaneously is locked in the power supply test point on the high level.So far, module is lockable, and reaches the purpose of protection.
For the output that the switch on above-mentioned control input or the out-put supply circuit comes power cutoff, switch not only can select for use the MOSFET pipe to realize, also can select other functionally similar devices realizations such as relay for use.
Testing circuit also can adopt power monitoring chip to realize that its principle is similar.
In the above-described embodiments, regenerative circuit adopts non-from lock control circuit, and therefore having introduced accessory power supply VC guarantees the overvoltage crowbar operate as normal.Can adopt the regenerative circuit of self-locking in addition, adopt and to add accessory power supply from lock control circuit.The regenerative circuit of self-locking can be by realizations such as triode or relays.
Claims (17)
1, a kind of guard method of overvoltage of power supply, this method can provide voltage to load by the power circuit that power module is formed, and it is characterized in that comprising step:
Output voltage to power module detects, and produces the overvoltage signal when overvoltage occurring;
To described power circuit, make this power circuit stop to power to the load described overvoltage signal feedback.
2, the method for claim 1 is characterized in that, makes the test point signal remain on overvoltage condition after detecting overvoltage.
3, method as claimed in claim 1 or 2 is characterized in that, described overvoltage signal feeds back in the power circuit by coupled modes.
4, method as claimed in claim 3 is characterized in that, described overvoltage signal feedback makes power module stop output voltage to the control end of power module.
5, method as claimed in claim 3 is characterized in that, described overvoltage signal feedback is to the mains switch of power module input mains side, makes the cut off the electricity supply input power supply of module of this mains switch.
6, the method for claim 1 is characterized in that, described overvoltage signal feedback makes this mains switch cut off the input power supply of load to the mains switch of power module out-put supply side.
7, the method for claim 1 is characterized in that, utilizes described overvoltage signal to produce alarm prompt.
8, a kind of power circuit comprises power module, it is characterized in that also comprising:
Testing circuit, its input is connected with the power output end of described power module; Be used to detect overvoltage;
Control circuit, its input is connected with the output of described testing circuit, and its output is connected with the control end of described power module; This control circuit is according to the voltage output of the detection signal control power module of testing circuit output.
9, power circuit as claimed in claim 8 is characterized in that also comprising:
Regenerative circuit, its input is connected with input with the output of described testing circuit respectively with output; Be used for when testing circuit output overvoltage signal the signal of the input of this testing circuit is maintained overvoltage condition.
10, power circuit as claimed in claim 8 or 9 is characterized in that described testing circuit comprises a comparator, and the sampled voltage that this comparator will obtain from power module output and reference voltage be output detection signal relatively afterwards.
11, power circuit as claimed in claim 8 is characterized in that, described control circuit comprises a coupled apparatus, and this coupled apparatus is isolated the input of described testing circuit and power module.
12, as claim 8 or 11 described power circuits, it is characterized in that described control circuit comprises a voltage-stabiliser tube, this voltage-stabiliser tube just often makes the voltage of control end stable at the power module output voltage.
13, a kind of power circuit comprises power module, it is characterized in that also comprising:
Mains switch is used to control the input power supply of power module or/and out-put supply;
Testing circuit, its input is connected with the power output end of described power module; Be used to detect overvoltage;
Control circuit, its input is connected with the output of described testing circuit, and its output is connected with described mains switch; This control circuit is according to the detection signal control mains switch of testing circuit output.
14, power circuit as claimed in claim 13 is characterized in that also comprising:
Regenerative circuit, its input is connected with input with the output of described testing circuit respectively with output; Be used for when testing circuit output overvoltage signal the signal of the input of this testing circuit is maintained overvoltage condition.
15, power circuit as claimed in claim 13 is characterized in that, described testing circuit comprises a comparator, and this comparator will be from the sampled voltage and the relatively back output detection signal of reference voltage of power module output acquisition.
16, power circuit as claimed in claim 13 is characterized in that, described control circuit comprises a coupled apparatus, and this coupled apparatus is coupled to mains switch with described detection signal.
As the arbitrary described power circuit of claim 13 to 16, it is characterized in that 17, described mains switch is metal-oxide-semiconductor, relay, triode or functionally similar device.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 03155472 CN1592019A (en) | 2003-08-30 | 2003-08-30 | Power supply overvoltage protecting method and power circuit thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 03155472 CN1592019A (en) | 2003-08-30 | 2003-08-30 | Power supply overvoltage protecting method and power circuit thereof |
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| CN1592019A true CN1592019A (en) | 2005-03-09 |
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| CN 03155472 Pending CN1592019A (en) | 2003-08-30 | 2003-08-30 | Power supply overvoltage protecting method and power circuit thereof |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101546962B (en) * | 2008-03-26 | 2011-08-24 | 鸿富锦精密工业（深圳）有限公司 | Power supply device |
| CN102651544A (en) * | 2012-03-27 | 2012-08-29 | 深圳市朗科电器有限公司 | Over-voltage protection method for field-effect transistor |
| CN101604282B (en) * | 2008-06-13 | 2012-08-29 | 鸿富锦精密工业（深圳）有限公司 | Voltage detection alarm device |
| CN103490391A (en) * | 2013-08-30 | 2014-01-01 | 宁波凯耀电器制造有限公司 | PWM output short-circuit protection circuit |
-
2003
- 2003-08-30 CN CN 03155472 patent/CN1592019A/en active Pending
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101546962B (en) * | 2008-03-26 | 2011-08-24 | 鸿富锦精密工业（深圳）有限公司 | Power supply device |
| US8310371B2 (en) | 2008-03-26 | 2012-11-13 | Hong Fu Jin Precision Industry (Shenzhen) Co., Ltd. | Power supply protection device |
| CN101604282B (en) * | 2008-06-13 | 2012-08-29 | 鸿富锦精密工业（深圳）有限公司 | Voltage detection alarm device |
| CN102651544A (en) * | 2012-03-27 | 2012-08-29 | 深圳市朗科电器有限公司 | Over-voltage protection method for field-effect transistor |
| CN102651544B (en) * | 2012-03-27 | 2015-04-15 | 深圳市朗科智能电气股份有限公司 | Over-voltage protection method for field-effect transistor |
| CN103490391A (en) * | 2013-08-30 | 2014-01-01 | 宁波凯耀电器制造有限公司 | PWM output short-circuit protection circuit |
| CN103490391B (en) * | 2013-08-30 | 2016-08-10 | 宁波凯耀电器制造有限公司 | A kind of PWM output short-circuit protection circuit |
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Open date: 20050309 |