CN208369203U - Primary side side power tube current sampling resistor short-circuit protection circuit - Google Patents
Primary side side power tube current sampling resistor short-circuit protection circuit Download PDFInfo
- Publication number
- CN208369203U CN208369203U CN201821135140.XU CN201821135140U CN208369203U CN 208369203 U CN208369203 U CN 208369203U CN 201821135140 U CN201821135140 U CN 201821135140U CN 208369203 U CN208369203 U CN 208369203U
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- sampling resistor
- output
- termination
- comparator
- power tube
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Abstract
The utility model provides a kind of primary side side power tube current sampling resistor short-circuit protection circuit, comprising: or the output end of an input termination first comparator U124 of door U224, the homophase input of first comparator U124 terminate the one end sampling resistor R110；The homophase input of second comparator U221 terminates minimum sampled voltage threshold value Vthcs_min；Vthcs_min<Vthcs；One end of the anti-phase input termination sampling resistor R110 of second comparator U221；The enable end of the output termination counter U223 of second comparator U221, when enabled termination high level of counter U223, are counted, and when enabled termination low level of counter U223 exports low level；The driving signal S201 of the input termination driving unit U123 output end of rising edge time delay module U222；The input terminal of the output termination counter U223 of rising edge time delay module U222, the output termination of counter U223 or the other end input terminal of door U224.The utility model precision is high, at low cost.
Description
Technical field
The utility model relates to a kind of switching power circuit, especially a kind of former pole side power tube current sampling resistor short circuit
Protect circuit.
Background technique
With the high speed development of the electronic products such as Internet of Things, mobile device, Switching Power Supply control technology is also being constantly brought forth new ideas
And iteration, it is desirable that stand-by power consumption is lower and lower, transfer efficiency is higher and higher, output is more and more accurate, periphery is increasingly simpler, valence
Lattice are increasingly cheaper, protection is more and more abundant etc..
The important feature that protection mechanism abundant has become switching power source chip is integrated, if FB opens short-circuit protection, was exported
Pressure, the protection of under-voltage, short-circuit protection, shorted diode, VDD over-voltage, under-voltage protection, line voltage over-voltage, under-voltage protection etc..But
The chip of integrated switch power original pole side power tube current sampling resistor short-circuit protection function is extremely rare in the market, and realizes
Mechanism is more special.
There is mirroring ratios relationship of the pole individual product by high-voltage power pipe, therefrom extracts a small gangs of electric current out and flow through in chip
One resistance in portion is greater than peak threshold reference voltage by ohmically pressure drop to control the shutdown of power tube, is thus used to
Realize Switching Power Supply original pole side power tube current sampling resistor short-circuit protection.This protection control mode has many defects, one
It is to be required to power tube, it is necessary to which integrated current mirror has current sample function, and cost will increase；The second is control precision without
Method guarantees；The third is application scheme requires, it is typically required specific scheme, lacks flexibility.
Currently, there are no see realizing the general of current sampling resistor short-circuit protection with ordinary power pipe on domestic and international market
Technology.
Summary of the invention
The purpose of the utility model is to overcome the deficiencies in the prior art, provide a kind of primary side side power tube current
Sampling resistor short-circuit protection circuit can realize current sampling resistor short-circuit protection function on ordinary power pipe, and application scheme is not
It is restricted, precision is high and at low cost.The technical solution adopted in the utility model is:
A kind of primary side side power tube current sampling resistor short-circuit protection circuit is suitable for a kind of switching power circuit；It is described
Switching power circuit includes: control circuit 120, power tube M101, sampling resistor R110；Wherein control circuit 120 includes power
Module U121, rest-set flip-flop U122, driving unit U123, first comparator U124 occur for pipe Continuity signal；
The end S of the output termination rest-set flip-flop U122 of module U121, the Q of rest-set flip-flop U122 occur for power tube Continuity signal
Terminate the input terminal of driving unit U123, the switch control terminal of the output termination power tube M101 of driving unit U123；Power tube
The current output terminal of M101 connects the one end sampling resistor R110, another termination primary side of sampling resistor R110；From sampling resistor
The sampled voltage Vcs that the one end R110 obtains connects the non-inverting input terminal of first comparator U124, and the reverse phase of first comparator U124 is defeated
Enter to terminate sampled voltage threshold value Vthcs；
The primary side side power tube current sampling resistor short-circuit protection circuit includes: that the second comparator U221, rising edge prolong
When module U222, counter U223 or door U224；
Or the output end of an input termination first comparator U124 of door U224, the homophase input of first comparator U124
Terminate the one end sampling resistor R110；The homophase input of second comparator U221 terminates minimum sampled voltage threshold value Vthcs_min；
Vthcs_min<Vthcs；One end of the anti-phase input termination sampling resistor R110 of second comparator U221；Second comparator U221
Output termination counter U223 enable end, when enabled termination high level of counter U223 counted, counter U223
Enabled termination low level when export low level；The input termination driving unit U123 output end of rising edge time delay module U222
Driving signal S201；The input terminal of the output termination counter U223 of rising edge time delay module U222；The output of counter U223
The other end input terminal of termination or door U224；Or the end R of the output termination rest-set flip-flop U122 of door U224.
Further, the minimum delay time of rising edge time delay module U222 must be greater than adopting on sampling resistor R110
Sample voltage Vcs rises the time for reaching Vthcs_min from minimum value.
Further, the maximum delay time of rising edge time delay module U222 must be smaller than power tube M101 electric current IM101
The time of transformer T106 magnetic saturation electric current is reached from minimum value.
Further, rising along time delay module U222 includes: PMOS tube P301, NMOS tube N301, voltage-controlled current source U311, electricity
Hold C301 and phase inverter U321；
The driving signal S201 of power tube is coupled with the grid of PMOS tube P301 and NMOS tube N301, PMOS tube P301's
Source electrode connects internal high level signal, and drain electrode is connected with the drain electrode of NMOS tube N301；
The source electrode of NMOS tube N301 meets voltage-controlled current source U311, the size of current of voltage-controlled current source U311 and Switching Power Supply
Busbar voltage VBUSDirect proportion is related；
One end of the leakage termination capacitor C301 of NMOS tube N301 and the input terminal of phase inverter U321；The other end of capacitor C301
Ground terminal；Output end of the output end of phase inverter U321 as rising edge time delay module U222.
Utility model has the advantages that
1) increased cost is seldom, and scheme is easy to accomplish.
2) control precision is high.
Detailed description of the invention
Fig. 1 is the schematic diagram of switching power circuit in the prior art.
Fig. 2 is the electrical schematic diagram of the utility model.
Fig. 3 is the rising edge time delay module schematic diagram of the utility model.
Specific embodiment
Below with reference to specific drawings and examples, the utility model is described in further detail.
Switching Power Supply in the prior art is as shown in Figure 1, whole including input rectifying filter circuit, transformer T106, output
Flow filter circuit, control circuit 120, power tube M101, sampling resistor R110；Wherein control circuit 120 is connected including power tube
Signal generating module U121, rest-set flip-flop U122, driving unit U123, first comparator U124；
The positive output of input rectifying filter circuit terminates transformer T106 primary side winding different name end, and negative output terminates primary side
Ground；Input rectifying filter circuit includes the bridge rectifier D101, filter capacitor C101 that diode is constituted；Transformer T106 is former
Side Motor Winding Same Name of Ends connects the current input terminal of power tube M101, and the current output terminal of power tube M101 meets sampling resistor R110 mono-
End, another termination primary side of sampling resistor R110；NMOS tube can be used in power tube M101, and drain electrode, source electrode are respectively as electricity
Input terminal and current output terminal are flowed, grid is as switch control terminal；The vice-side winding of transformer T106 connects output rectification filter
Circuit exports DC voltage by output rectifier and filter；Output rectifier and filter may include rectifier diode D102,
Filter capacitor C102, output resistance R102 etc., this part is the custom circuit of the prior art, is repeated no more；
The end S of the output termination rest-set flip-flop U122 of module U121, the Q of rest-set flip-flop U122 occur for power tube Continuity signal
Terminate the input terminal of driving unit U123, the switch control terminal of the output termination power tube M101 of driving unit U123；From sampling
The sampled voltage Vcs that the one end resistance R110 obtains connects the non-inverting input terminal of first comparator U124, and first comparator U124's is anti-
Mutually input termination sampled voltage threshold value Vthcs；Sampled voltage threshold value Vthcs is a reference signal；First comparator U124's
The end R of output termination rest-set flip-flop U122；By power tube Continuity signal module U121 control, function occur for the unlatching of power tube M101
The shutdown of rate pipe M101 is controlled by first comparator U124；
Power tube current sampling resistor short-circuit protection circuit in primary side side provided by the utility model, as shown in Fig. 2, in Fig. 1
On the basis of increase: the second comparator U221, rising edge time delay module U222, counter U223 or door U224；
Or the output end of an input termination first comparator U124 of door U224, the homophase input of first comparator U124
The one end sampling resistor R110 is terminated, the anti-phase input of first comparator U124 terminates sampled voltage threshold value Vthcs；Second comparator
The homophase input of U221 terminates minimum sampled voltage threshold value Vthcs_min；Vthcs_min<Vthcs；Second comparator U221's
One end of anti-phase input termination sampling resistor R110；The enable end of the output termination counter U223 of second comparator U221, meter
It is counted when the enabled termination high level of number device U223；The input termination driving unit U123 of rising edge time delay module U222 is defeated
The driving signal S201 of outlet；The input terminal of the output termination counter U223 of rising edge time delay module U222；Counter U223
Output termination or door U224 other end input terminal；Or the end R of the output termination rest-set flip-flop U122 of door U224；
When sampling resistor R110 is normally connected, the sampled voltage Vcs that obtains on sampling resistor R110 can be with flowing through function
The increase of rate pipe M101 electric current and increase, in the delay time of rising edge time delay module U222, Vcs be greater than Vthcs when (Vcs
Also greater than Vthcs_min), the output of the second comparator U221 is low level, therefore the output of the second comparator U221 is zero, meter
Number device U223 output is low level, under these conditions, the shutdown of the power tube M101 only output by first comparator U124
High level control；
The minimum delay time of rising edge time delay module U222 must be greater than the sampled voltage Vcs on sampling resistor R110
Rise the time for reaching Vthcs_min from minimum value；
The maximum delay time of rising edge time delay module U222 must be smaller than power tube M101 electric current IM101From minimum value
Reach the time of transformer T106 magnetic saturation electric current；
The delay time of rising edge time delay module U222 in [minimum delay time, maximum delay time] within the scope of this,
Without both ends endpoint；
When sampling resistor R110 is to ground short circuit, the sampled voltage Vcs on sampling resistor R110 remains zero, accordingly
Ground, the output signal of the second comparator U221 are high level, and counter U223 starts to work；The driving of driving unit U123 output
Signal S201 is input to rising edge time delay module U222, and after delay time Td, the output of rising edge time delay module U222 is believed
Number S202 is also got higher by low；In a switch periods, counter U223 export a high level, by or door U224 after reset
The end Q of rest-set flip-flop U122, rest-set flip-flop U122, which are exported from high level, becomes low level, correspondingly, driving unit U123 output
Driving signal S201 low level is also become from high level, power tube M101 shutdown；In continuous several switch periods, work as power
When pipe M101 is connected, all there is the second comparator U221 and rising edge time delay module U222 while exporting high level, then counter
U223 output is locked in high level, indicates the short circuit of primary side side power tube current sampling resistor；When counter U223 output is locked in
After high level, power tube M101 is no longer turned on, and this state continues maintained until restoring after switching power circuit power-down rebooting；
As shown in figure 3, rising edge time delay module U222 includes: PMOS tube P301, NMOS tube N301, voltage-controlled current source
U311, capacitor C301 and phase inverter U321；
The driving signal S201 of power tube is coupled with the grid of PMOS tube P301 and NMOS tube N301, PMOS tube P301's
Source electrode connects internal high level signal " 1 ", and drain electrode is connected with the drain electrode of NMOS tube N301；
The source electrode of NMOS tube N301 meets voltage-controlled current source U311, the size of current of voltage-controlled current source U311 and Switching Power Supply
Busbar voltage VBUSDirect proportion is related；
One end of the leakage termination capacitor C301 of NMOS tube N301 and the input terminal of phase inverter U321；The other end of capacitor C301
Ground terminal；Output end of the output end of phase inverter U321 as rising edge time delay module U222；
When S201 signal is low level, NMOS tube N301 shutdown is connected in PMOS tube P301, is high level on capacitor C301,
It is low level by exporting S202 signal after phase inverter U321；After S201 signal is by low get higher, PMOS tube P301 turns off NMOS
Pipe N301 conducting, capacitor C301 are discharged over the ground by N301 and U311, and discharge time will continue several microseconds, when on capacitor C301
Voltage higher than phase inverter U321 inversion threshold before, output signal S202 keep low level, the voltage on capacitor C301
After inversion threshold lower than phase inverter U321, output signal S202 is got higher by low, is realized to S201 signal rising edge delays time to control；
U311 is a voltage-controlled current source, and input control signal is related to the size of voltage of VBUS, generate one with
The electric current of the microampere order of voltage of VBUS size variation；Rising edge delay time can be obtained from following equation；
T in formuladIndicate delay time, C301 is the capacitance in Fig. 3, VthU301It is the inversion threshold of phase inverter U301, K
It is conversion coefficient, VBUSIt is busbar voltage；Wherein C301, VthU301, K is constant, therefore delay time TdSize and bus
Voltage swing VBUSIn inverse ratio.
After the output signal S202 of rising edge time delay module U222 is by low get higher, since counter U223 exports high electricity at once
It is flat, rest-set flip-flop U122 is resetted, driving signal S201 switchs to low level at once, and thus signal S202 can within a very short time again
It is lower, therefore signal S202 is a narrow pulse signal.
Merely exemplary, the utility model has been applied to flyback power supply converter.It will be appreciated that this is practical new
Type has wider application range.
It should be noted last that the above specific embodiment is only to illustrate the technical solution of the utility model rather than limits
System, although the utility model is described in detail referring to example, those skilled in the art should understand that, it can be right
The technical solution of the utility model is modified or replaced equivalently, without departing from the spirit and model of technical solutions of the utility model
It encloses, should all cover in the scope of the claims of the utility model.
Claims (5)
1. a kind of primary side side power tube current sampling resistor short-circuit protection circuit is suitable for a kind of switching power circuit；It is described to open
Powered-down source circuit includes: control circuit 120, power tube M101, sampling resistor R110；Wherein control circuit 120 includes power tube
Module U121, rest-set flip-flop U122, driving unit U123, first comparator U124 occur for Continuity signal；
The end S of the output termination rest-set flip-flop U122 of module U121, the Q termination of rest-set flip-flop U122 occur for power tube Continuity signal
The input terminal of driving unit U123, the switch control terminal of the output termination power tube M101 of driving unit U123；Power tube M101
Current output terminal connect the one end sampling resistor R110, another termination primary side of sampling resistor R110；From sampling resistor R110 mono-
The sampled voltage Vcs that end obtains connects the non-inverting input terminal of first comparator U124, the anti-phase input termination of first comparator U124
Sampled voltage threshold value Vthcs；
It is characterized in that, the primary side side power tube current sampling resistor short-circuit protection circuit include: the second comparator U221, on
It rises along time delay module U222, counter U223 or door U224；
Or the output end of an input termination first comparator U124 of door U224, the homophase input termination of first comparator U124
The one end sampling resistor R110；The homophase input of second comparator U221 terminates minimum sampled voltage threshold value Vthcs_min；Vthcs_
min<Vthcs；One end of the anti-phase input termination sampling resistor R110 of second comparator U221；The output of second comparator U221
The enable end of counter U223 is terminated, when enabled termination high level of counter U223 is counted, and counter U223's is enabled
Low level is exported when terminating low level；The driving letter of the input termination driving unit U123 output end of rising edge time delay module U222
Number S201；The input terminal of the output termination counter U223 of rising edge time delay module U222；The output of counter U223 terminate or
The other end input terminal of door U224；Or the end R of the output termination rest-set flip-flop U122 of door U224.
2. power tube current sampling resistor short-circuit protection circuit in primary side side as described in claim 1, which is characterized in that
The minimum delay time of rising edge time delay module U222 must be greater than the sampled voltage Vcs on sampling resistor R110 from most
Small value rises the time for reaching Vthcs_min.
3. power tube current sampling resistor short-circuit protection circuit in primary side side as described in claim 1, which is characterized in that
The maximum delay time of rising edge time delay module U222 must be smaller than power tube M101 electric current IM101It reaches and becomes from minimum value
The time of depressor T106 magnetic saturation electric current.
4. power tube current sampling resistor short-circuit protection circuit in primary side side as described in claim 1, which is characterized in that
Rising along time delay module U222 includes: PMOS tube P301, NMOS tube N301, voltage-controlled current source U311, capacitor C301 and reverse phase
Device U321；
The driving signal S201 of power tube is coupled with the grid of PMOS tube P301 and NMOS tube N301, the source electrode of PMOS tube P301
Internal high level signal is connect, drain electrode is connected with the drain electrode of NMOS tube N301；
The source electrode of NMOS tube N301 connects voltage-controlled current source U311, the size of current of voltage-controlled current source U311 and the bus of Switching Power Supply
Voltage VBUSDirect proportion is related；
One end of the leakage termination capacitor C301 of NMOS tube N301 and the input terminal of phase inverter U321；The other end of capacitor C301 is grounded
End；Output end of the output end of phase inverter U321 as rising edge time delay module U222.
5. power tube current sampling resistor short-circuit protection circuit in primary side side as described in claim 1, which is characterized in that
When sampling resistor R110 is to ground short circuit, the sampled voltage Vcs on sampling resistor R110 remains zero, correspondingly, second
The output signal of comparator U221 is high level, and counter U223 starts to work；The driving signal of driving unit U123 output
S201 is input to rising edge time delay module U222, after delay time Td, the output signal of rising edge time delay module U222
S202 is also got higher by low；In a switch periods, counter U223 export a high level, by or door U224 after reset RS
The end Q of trigger U122, rest-set flip-flop U122, which are exported from high level, becomes low level, correspondingly, driving unit U123 output
Driving signal S201 also becomes low level, power tube M101 shutdown from high level；In continuous several switch periods, work as power tube
When M101 is connected, all there is the second comparator U221 and rising edge time delay module U222 while exporting high level, then counter
U223 output is locked in high level, and this state continues maintained until restoring after switching power circuit power-down rebooting.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201821135140.XU CN208369203U (en) | 2018-07-18 | 2018-07-18 | Primary side side power tube current sampling resistor short-circuit protection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201821135140.XU CN208369203U (en) | 2018-07-18 | 2018-07-18 | Primary side side power tube current sampling resistor short-circuit protection circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN208369203U true CN208369203U (en) | 2019-01-11 |
Family
ID=64925568
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201821135140.XU Withdrawn - After Issue CN208369203U (en) | 2018-07-18 | 2018-07-18 | Primary side side power tube current sampling resistor short-circuit protection circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN208369203U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108649537A (en) * | 2018-07-18 | 2018-10-12 | 无锡硅动力微电子股份有限公司 | Primary side side power tube current sampling resistor short-circuit protection circuit |
| CN112165067A (en) * | 2020-09-03 | 2021-01-01 | 四川遂宁市利普芯微电子有限公司 | Overcurrent protection circuit |
-
2018
- 2018-07-18 CN CN201821135140.XU patent/CN208369203U/en not_active Withdrawn - After Issue
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108649537A (en) * | 2018-07-18 | 2018-10-12 | 无锡硅动力微电子股份有限公司 | Primary side side power tube current sampling resistor short-circuit protection circuit |
| CN108649537B (en) * | 2018-07-18 | 2023-10-03 | 无锡硅动力微电子股份有限公司 | Primary side power tube current sampling resistor short-circuit protection circuit |
| CN112165067A (en) * | 2020-09-03 | 2021-01-01 | 四川遂宁市利普芯微电子有限公司 | Overcurrent protection circuit |
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| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| AV01 | Patent right actively abandoned |
Granted publication date: 20190111 Effective date of abandoning: 20231003 |
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| AV01 | Patent right actively abandoned |
Granted publication date: 20190111 Effective date of abandoning: 20231003 |
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| AV01 | Patent right actively abandoned | ||
| AV01 | Patent right actively abandoned |