CN203193494U - A load impedance testing BOOST output safety control circuit - Google Patents
A load impedance testing BOOST output safety control circuit Download PDFInfo
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- CN203193494U CN203193494U CN 201220667182 CN201220667182U CN203193494U CN 203193494 U CN203193494 U CN 203193494U CN 201220667182 CN201220667182 CN 201220667182 CN 201220667182 U CN201220667182 U CN 201220667182U CN 203193494 U CN203193494 U CN 203193494U
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Abstract
The utility model provides a load impedance testing BOOST output safety control circuit and is aimed at enabling a BOOST power circuit to reliably supply electricity for a load device. The load impedance testing BOOST output safety control circuit comprises a reference voltage source, a comparator A, a comparator B, a triode N1, and a voltage-regulator tube Z5. The input end of the output safety control circuit is connected with BOOST DC output voltage, while the output end of the output safety control circuit is connected with a load. A main loop circuit where the input end and the output end of the output safety control circuit are arranged is connected with a VMOS tube M5 and a current-limiting resistor R24 in series. The base electrode of the VMOS tube M5 is connected with the negative end of the output end of the output safety control circuit through the triode N1. The base electrode of the triode N1 is connected with the reference voltage source. The output end of the output safety control circuit is connected with a filtering capacitor and a feedback branch in parallel. The feedback branch is successively connected with a divider resistor R14 and a RC circuit in series. The load impedance testing BOOST output safety control circuit is capable of guaranteeing BOOST output to be automatically adjusted when the load causes short circuit, and achieving current-limiting output while guaranteeing low power consumption.
Description
Technical field
The present invention relates to a kind of safety control circuit, can be used as the intermediate circuit between BOOST power circuit and the load.
Background technology
DC power supply can be simple independent current source, as storage battery, also can be to obtain the DC power supply that needs by straight straight conversion or by rectifying and wave-filtering method conversion AC power.In the prior art; in order to prevent short circuit, protection DC source; in the circuit with DC power supply; and in the charging circuit of storage battery; be connected in series fuse in input circuit, in case be short-circuited, electric current is excessive in the circuit; fuse will fuse, thereby has avoided super-high-current to burn out DC source.
For example for the BOOST power circuit, when load equipment is carried out low-voltage power supply, need to guarantee the fail safe of power supply more, do not increase extra power consumption in addition as far as possible.
Short-circuit protection circuit is the important circuit of protection DC source, and its performance quality directly has influence on safety and the work of DC source and load.The existing short-circuit protection circuit that adopts serial connection fuse mode; certain parts damages in load circuit cause short circuit; perhaps because human operational error when the both positive and negative polarity of DC source is connect short circuit; be easy to make the serial connection blown fuse; the fuse that needs the machine of tearing open more to renew after the blown fuse so then greatly influences load and works continuously and stably.Therefore, more reliable short-circuit protection circuit need be arranged, to keep the work of load equipment continuous high-efficient ground.
Summary of the invention
The invention provides a kind of load impedance test formula BOOST output safety control circuit, thereby the BOOST power circuit is powered more reliably to load equipment, the work of continuous high-efficient ground.
The invention provides following basic scheme:
Load impedance test formula BOOST output safety control circuit comprises reference voltage source, comparator A, comparator B, triode N1 and voltage-stabiliser tube Z5; The input termination BOOST VD of this output safety control circuit, the load of output termination, series connection is provided with VMOS pipe M5 and current-limiting resistance R24 on the major loop at described input and output place, wherein, the base stage of VMOS pipe M5 is connected to the negative terminal of described output through triode N1, and the base stage of triode N1 is connected to described reference voltage source; Described output is parallel with a filter capacitor C15 and a feedback branch, is in series with divider resistance R14 and RC circuit on this feedback branch successively;
The normal phase input end of comparator A inserts this feedback branch, be connected to the anode of described output through divider resistance R14, the negative-phase input of comparator A connects reference voltage, and the output of comparator A is connected to the negative terminal of described input successively through resistance R 13, resistance R 27, the resistance R 22 of series connection;
The normal phase input end of comparator B inserts the series arm at resistance R 13, resistance R 27 and resistance R 22 places, and its access node is between resistance R 27 and resistance R 22; The negative-phase input of comparator B is connected to the negative terminal of described output through resistance R 6; The output of comparator B is connected to the base stage of triode N1.
Based on above-mentioned basic scheme, can also carry out following optimization and limit and improve: draw a branch road and manage the source electrode of M5 to VMOS between the drain electrode of the base stage of VMOS pipe M5 and triode N1, this branch road is provided with voltage-stabiliser tube Z1.Described reference voltage is provided by the described voltage-stabiliser tube Z5 that connects with described reference voltage source.The access node of the normal phase input end of comparator B also is connected to described output by filter capacitor C16
Negative terminal.Comparator A and comparator B constitute a two encapsulation comparator.The preferred LH2903 of this pair encapsulation comparator, LM2903 or other similar device.
The present invention has the following advantages:
Output protection circuit provided by the invention (being described load impedance test formula BOOST output safety control circuit) can guarantee that BOOST output adjusts automatically when load short circuits, current limliting output still guarantees low-power consumption simultaneously.
Description of drawings
Fig. 1 is the structural representation of output protection circuit of the present invention.
Fig. 2 is the overall structure schematic diagram of the output protection circuit of invention.
Embodiment
The input termination direct current output of output safety control circuit of the present invention, the load of output termination.The output that is DC power supply provides burning voltage through this output safety control circuit to load.
As Fig. 1-shown in Figure 2, this output safety control circuit comprises that comparator A and comparator B are encapsulated as a dual comparator among reference voltage source, comparator A, the comparator B(figure), triode N1 and voltage-stabiliser tube Z5; Series connection is provided with VMOS pipe M5 and current-limiting resistance R24 on the major loop at described input and output place, and wherein, the base stage of VMOS pipe M5 is connected to the negative terminal of described output through triode N1, and the base stage of triode N1 is connected to described reference voltage source; Described output is parallel with a filter capacitor and a feedback branch, is in series with divider resistance R14 and RC circuit on this feedback branch successively;
The normal phase input end of comparator A inserts this feedback branch, be connected to the anode of described output through divider resistance R14, the negative-phase input of comparator A connects reference voltage, and the output of comparator A is connected to the negative terminal of described input successively through resistance R 13, resistance R 27, the resistance R 22 of series connection;
The normal phase input end of comparator B inserts the series arm at resistance R 13, resistance R 27 and resistance R 22 places, and its access node is between resistance R 27 and resistance R 22; The negative-phase input of comparator B is connected to the negative terminal of described output through resistance R 6; The output of comparator B is connected to the base stage of triode N1.
Draw a branch road and manage the source electrode of M5 to VMOS between the drain electrode of the base stage of VMOS pipe M5 and triode N1, this branch road is provided with voltage-stabiliser tube Z1.Described reference voltage is provided by the 2.5V voltage-stabiliser tube of connecting with described reference voltage source.The access node of the normal phase input end of comparator B also is connected to the negative terminal of described output by filter capacitor.
The preferred LH2903 of two encapsulation comparators, LM2903 or other similar devices of comparator A and comparator B formation; Can certainly adopt discrete component to realize.
IC5 is standard high-speed comparator circuit (dual comparator), and comparator B, N1, M5 form constant-current control circuit.B-terminal voltage V3=0V, the B+ terminal voltage is:
V2=R22×V1/(R22+R27)-Us
In the following formula, Us=Is * Rs=Is * R24
V1 voltage is controlled by comparator A, A-terminal voltage VR=2.5V, and the A+ terminal voltage is: VL=UL * R7/ (R7+R14)=RL * Is.
1, current-limited startup
During circuit start (powering on), VL ﹤ 2.5V, comparator A output is low, and then R13 inserts dividing potential drop.
Wherein: R13 ﹤ ﹤ R25, R13 ﹤ ﹤ R27, VR=2.5V;
V1≈VR×R13/(R13+R25)=2.5×R13/(R13+R25)
V2=R22×V1/(R22+R27)-Us=R22×(2.5×R13/(R13+R25))/(R22+R27)-Us=2.5×R22×R13/((R13+R25)(R22+R27))-Is×Rs
If: c1=2.5 * R22 * R13/ ((R13+R25) (R22+R27))
That is: V2=c1-Rs * Is
When V2=c1-Rs * Is ≦ 0, comparator B, N1, the output of M5 current limliting, cut-off current is: Is=c1/Rs.
Can guarantee that namely BOOST output starts with current limliting (Is=c1/Rs).
VL=UL×R7/(R7+R14)=RL×Is=c1×RL/Rs
Therefore, only need the corresponding resistance of configuration, when making BOOST load impedance less (short circuit), VL ﹤ 2.5V is operated under the safe limited current state.Such as, according to Is=c1/Rs, Is is set between routine value 1/4-1/10.
2, operating conventional current limliting comparator A output high (open circuit) when BOOST load impedance fault-free VL ≧ 2.5V, R13 disengaging dividing potential drop then, V2=2.5 * R22/ (R22+R27+R25)-Us;
If: c2=2.5 * R22/ (R22+R27+R25)
That is: V2=c2-Rs * IL
When V2=c2-Rs * IL ≦ 0, comparator B, N1, the output of M5 current limliting, cut-off current is: IL=c2/Rs,
Can guarantee that namely BOOST output works with current limliting (IL=c2/Rs).
Therefore, only need the corresponding resistance of configuration, make IL greater than running current, and make VMOS
Be limited in the safe range of electric current, power.Usually, IL is set between 1.1 times to 1.5 times of conventional value.
3, the low-power consumption of operate as normal
During BOOST output operate as normal, output current is less than IL, and comparator (A, B) is exported high (open circuit), and P raceway groove VMOS (M5) is operated in ultralow conducting resistance (R
DS=0.005 Ω) under the state.
For example: power output 200W output voltage 50V, then output current is: Io=200/50=4A,
VMOS (M5) goes up pressure drop: 4 * 0.005=0.02,
VMOS (M5) control power consumption is: Pe=0.02 * 4=0.08W, as can be seen, the control power consumption when normally moving is very low.
4, short-circuit protection
If in the BOOST circuit working process if fault such as output short-circuit takes place, cause VL ﹤ 2.5V, then comparator A output is low, make comparator B, N1, M5 current limliting output (referring to aforementioned the 1st kind of situation), circuit reenters clean boot (Is) state, after fault was eliminated, BOOST recovered normal output automatically.
Claims (6)
1. load impedance test formula BOOST output safety control circuit is characterized in that: comprise reference voltage source, comparator A, comparator B, triode N1 and voltage-stabiliser tube Z5; The input termination BOOST VD of this output safety control circuit, the load of output termination, series connection is provided with VMOS pipe M5 and current-limiting resistance R24 on the major loop at described input and output place, wherein, the base stage of VMOS pipe M5 is connected to the negative terminal of described output through triode N1, and the base stage of triode N1 is connected to described reference voltage source; Described output is parallel with a filter capacitor C15 and a feedback branch, is in series with divider resistance R14 and RC circuit on this feedback branch successively;
The normal phase input end of comparator A inserts this feedback branch, be connected to the anode of described output through divider resistance R14, the negative-phase input of comparator A connects reference voltage, and the output of comparator A is connected to the negative terminal of described input successively through resistance R 13, resistance R 27, the resistance R 22 of series connection;
The normal phase input end of comparator B inserts the series arm at resistance R 13, resistance R 27 and resistance R 22 places, and its access node is between resistance R 27 and resistance R 22; The negative-phase input of comparator B is connected to the negative terminal of described output through resistance R 6; The output of comparator B is connected to the base stage of triode N1.
2. load impedance according to claim 1 test formula BOOST output safety control circuit is characterized in that: draw a branch road and manage the source electrode of M5 to VMOS between the drain electrode of the base stage of VMOS pipe M5 and triode N1, this branch road is provided with voltage-stabiliser tube Z1.
3. load impedance according to claim 1 is tested formula BOOST output safety control circuit, and it is characterized in that: described reference voltage is provided by the described voltage-stabiliser tube Z5 that connects with described reference voltage source.
4. load impedance according to claim 1 is tested formula BOOST output safety control circuit, and it is characterized in that: the access node of the normal phase input end of comparator B also is connected to the negative terminal of described output by filter capacitor C16.
5. load impedance test formula BOOST output safety control circuit according to claim 1 is characterized in that: two encapsulation comparator of comparator A and comparator B formation.
6. load impedance test formula BOOST output safety control circuit according to claim 5 is characterized in that: described two encapsulation comparators employing LH2903 or LM2903.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220667182 CN203193494U (en) | 2012-11-30 | 2012-11-30 | A load impedance testing BOOST output safety control circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220667182 CN203193494U (en) | 2012-11-30 | 2012-11-30 | A load impedance testing BOOST output safety control circuit |
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| CN203193494U true CN203193494U (en) | 2013-09-11 |
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| CN 201220667182 Expired - Fee Related CN203193494U (en) | 2012-11-30 | 2012-11-30 | A load impedance testing BOOST output safety control circuit |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103001476A (en) * | 2012-11-30 | 2013-03-27 | 西安智海电力科技有限公司 | Load impedance test type BOOST output safety control circuit |
| FR3046891A1 (en) * | 2016-01-15 | 2017-07-21 | Continental Automotive France | SWITCHING PILOT INCORPORATING A MEANS OF ESTIMATING THE IMPEDANCE OF THE PILOT CHARGE |
-
2012
- 2012-11-30 CN CN 201220667182 patent/CN203193494U/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103001476A (en) * | 2012-11-30 | 2013-03-27 | 西安智海电力科技有限公司 | Load impedance test type BOOST output safety control circuit |
| CN103001476B (en) * | 2012-11-30 | 2016-04-27 | 西安智海电力科技有限公司 | Load impedance test type BOOST output safety control circuit |
| FR3046891A1 (en) * | 2016-01-15 | 2017-07-21 | Continental Automotive France | SWITCHING PILOT INCORPORATING A MEANS OF ESTIMATING THE IMPEDANCE OF THE PILOT CHARGE |
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| C14 | Grant of patent or utility model | ||
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| 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: 20130911 Termination date: 20161130 |