CN101330203A - Current deep constant-current output driving circuit with load short circuit protection function - Google Patents
Current deep constant-current output driving circuit with load short circuit protection function Download PDFInfo
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- CN101330203A CN101330203A CNA2008100456875A CN200810045687A CN101330203A CN 101330203 A CN101330203 A CN 101330203A CN A2008100456875 A CNA2008100456875 A CN A2008100456875A CN 200810045687 A CN200810045687 A CN 200810045687A CN 101330203 A CN101330203 A CN 101330203A
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Abstract
The invention belongs to the electronic technical field, and relates to a constant current outputting and driving circuit of a current sink, which has the load short circuit protecting function. The constant current outputting and driving circuit comprises a driving unit and a load short circuit protecting unit, wherein, the driving unit provides a drive working current for load; the load short circuit protecting unit comprises a sampling circuit, a comparing circuit and a control signal output/turn-off circuit; when the load normally works, the load short circuit protecting unit provides a control signal for the power switch tube of the driving unit; when the load has a short circuit, the load short circuit protecting unit outputs low level, thereby automatically cutting off the power switch tube of the driving unit, protecting the whole driving circuit, and avoiding the chip damage caused by the overlarge current during the load short circuit. As the source end of a sampling MOS tube is connected with the input end, the constant current outputting and driving circuit is high voltage resistant, and does not need an additional ESD structure; at the same time, the adopted circuit elements are basic circuit elements such as logic gates, selectors, MOS tubes, capacitors, etc., thereby having the advantages of low cost, simple structure, good reliability, etc. The constant current outputting and driving circuit can be not only applied to the LED drive.
Description
Technical field
The invention belongs to electronic technology field, relate to the current deep constant-current output driving circuit, especially have the current deep constant-current output driving circuit of load short circuit protection function.
Background technology
At present, along with the continuous development of electronic application, the drive circuit of current deep constant-current output is more and more.Wherein the big screen LED display screen is a significant example.It has been widely used in stadiums, city and public square, traffic, corporate image propaganda, commercial advertisement and other application.The LED display technical barrier is captured substantially, and brightness, the quality of light-emitting display device become more consummate day by day, and price also further reduces, and market development is increasingly mature, and demand increases day by day.To drive circuit, in order to improve reliability, various protective circuits need become better and approaching perfection day by day.Owing to many-sided reason, the phenomenon that is short-circuited easily of LED load at present; So, when the LED load short circuits, also just become the problem of necessary solution for the protection of drive circuit.When load short circuits, load voltage all is added on the output stage of drive circuit, and the power consumption of drive circuit is increased greatly, when power consumption exceeds the scope that drive circuit can bear, drive circuit will be burnt out, thereby brings adverse influence for system applies and maintenance.
Fig. 1 is existing current deep constant-current output driving circuit schematic diagram, does not have short-circuit protection circuit in its export structure.When load was short-circuited phenomenon, load voltage all was added on the drive circuit like this, thereby very easily burnt out drive circuit, and system reliability is reduced greatly.And the needs that existing load short circuits protective circuit has take very big chip area, and what have needs electrostatic discharge (ESD), thereby cause the drive circuit chip cost high.
Summary of the invention
The present invention overcomes the deficiency of existing current deep constant-current output driving circuit load short circuit protection function, has proposed a kind of circuit structure that can just can carry out short-circuit protection with element seldom.When load was short-circuited, short-circuit protection circuit turn-offed the driving power pipe of drive circuit at once, thereby has protected drive circuit.This circuit has advantages such as low, the simple in structure and good reliability of cost simultaneously.
Technical solution of the present invention is as follows:
Current deep constant-current output driving circuit with load short circuit protection function as shown in Figure 2, comprises driver element and load short circuits protected location.Driver element is made up of an operational amplifier OP1, resistance R 1, resistance R 2, first selector SEL1 and NMOS power switch pipe M3; The substrate ground connection of NMOS power switch pipe M3, its source electrode is by resistance R 1 ground connection, and its grid meets the selection signal output part Y of first selector SEL1; Second of first selector SEL1 selects signal input part B by resistance R 2 ground connection, and first of first selector SEL1 selects signal input part A to connect the output of operational amplifier OP1; When the first selector selecting side was high level, its first selection signal input part A linked to each other with selecting signal output part Y; When the first selector selecting side was low level, its second selection signal input part B linked to each other with selecting signal output part Y; The external reference voltage Vref of the positive input terminal of operational amplifier OP1, its negative input end connects the source electrode of NMOS power switch pipe M3.The drain electrode of the NMOS power switch pipe M3 of the voltage sample termination driver element of load short circuits protected location; the control signal PWM of the input termination NMOS power switch pipe M3 of load short circuits protected location, the control signal output ends of load short circuits protected location meets the selecting side S of the first selector SEL1 of driver element.
When the current deep constant-current output driving circuit with load short circuit protection function of the present invention was specifically used, load (as LED) was connected between the drain electrode and load voltage Vloadup of NMOS power switch pipe M3.When the load operate as normal, the control signal PWM of the control signal output ends of load short circuits protected location output NMOS power switch pipe M3; When load short circuits, the control signal output ends output low level signal of load short circuits protected location turn-offs NMOS power switch pipe M3, in time protects drive circuit to be unlikely to be burnt.
Current deep constant-current output driving circuit with load short circuit protection function of the present invention, the circuit element of employing is basic circuit elements such as some gates, metal-oxide-semiconductor, selector and electric capacity, has advantages such as cost is low, simple in structure, good reliability.Simple in structure, easy to use and characteristics that versatility is good that entire circuit has.Simultaneously, in the current deep constant-current output driving circuit with load short circuit protection function of the present invention, the sampling metal-oxide-semiconductor of load short circuits protected location is that the source terminates at output, can be high pressure resistant, do not need the ESD structure, and therefore have electrostatic-proof function.
Description of drawings
Fig. 1 is a kind of typical current current deep constant export structure schematic diagram.
Fig. 2 is the current deep constant-current output driving circuit structural representation with load short circuits protected location.
Fig. 3 is current deep constant-current output driving circuit embodiment one circuit diagram that the present invention has load short circuit protection function.
Fig. 4 is current deep constant-current output driving circuit embodiment two circuit diagrams that the present invention has load short circuit protection function.
Fig. 5 is the current deep constant-current output driving circuit embodiment three-circuit figure that the present invention has load short circuit protection function.
Fig. 6 is current deep constant-current output driving circuit embodiment four circuit diagrams that the present invention has load short circuit protection function.
Fig. 7 is current deep constant-current output driving circuit embodiment five circuit diagrams that the present invention has load short circuit protection function.
Embodiment
Need to prove, the current deep constant-current output driving circuit with load short circuit protection function of the present invention, its load short circuits protected location mainly is made up of sample circuit, comparison circuit and control signal output/breaking circuit.Concrete form such as Fig. 3 are to shown in Figure 7.
Execution mode one (as shown in Figure 3):
Current deep constant-current output driving circuit with load short circuit protection function comprises driver element and load short circuits protected location.
Driver element is made up of an operational amplifier OP1, resistance R 1, resistance R 2, first selector SEL1 and NMOS power switch pipe M3; The substrate ground connection of NMOS power switch pipe M3, its source electrode is by resistance R 1 ground connection, and its grid meets the selection signal output part Y of first selector SEL1; Second of first selector SEL1 selects signal input part B by resistance R 2 ground connection, and first of first selector SEL1 selects signal input part A to connect the output of operational amplifier OP1; When the first selector selecting side was high level, its first selection signal input part A linked to each other with selecting signal output part Y; When the first selector selecting side was low level, its second selection signal input part B linked to each other with selecting signal output part Y; The external reference voltage Vref of the positive input terminal of operational amplifier OP1, its negative input end connects the source electrode of NMOS power switch pipe M3.
The load short circuits protected location is made up of sample circuit, comparison circuit and control signal output/breaking circuit: described sample circuit manages M1, NMOS pipe M2 by PMOS and capacitor C 1 is formed; Described comparison circuit is made of the first inverter INV1; Described control signal output/breaking circuit is made up of the second inverter INV2 and second selector SEL2, third selector SEL3.Second selector SEL2 is identical with the structure of third selector SEL3: when promptly selecting side S is high level first input end A is linked to each other with output Y, then the second input B is linked to each other with output Y if instead select when end S is low level.The source electrode of PMOS pipe M1 connects the drain electrode of NMOS power switch pipe M3 in the driver element, and the drain electrode of PMOS pipe M1 is by capacitor C 1 ground connection, and the grid of PMOS pipe M1 connects the output of the second inverter INV2 and the grid of NMOS pipe M2; The source ground of NMOS pipe M2, its drain electrode connect the drain electrode of PMOS pipe M1 and the input of the first inverter INV1; The selecting side S of the output termination second selector SEL2 of the first inverter INV1 and the selecting side S of third selector SEL3; First of second selector SEL2 selects input A and third selector SEL3 first to select input A to meet the drive control signal PWM of NMOS power switch pipe M3 in the driver element, second of second selector SEL2 selects input B to meet supply voltage VDD, second of third selector SEL3 selects input B by resistance R 3 ground connection, the output Y of second selector SEL2 connects the input of the second inverter INV1, and the output Y of third selector SEL3 meets the selecting side S of first selector in the driver element.
When technique scheme was specifically used, load (as LED) was connected between the drain electrode and load voltage Vloadup of NMOS power switch pipe M3.When the load operate as normal; the output control signal PWM_OUT of the control signal output ends of load short circuits protected location is exactly the control signal PWM of NMOS power switch pipe M3: when PWM is that high level is when opening NMOS power switch pipe M3; PMOS pipe M1 conducting; charging voltage to capacitor C 1 is that Vloadup deducts the pressure drop in the load; do not reach the comparative voltage of comparison circuit, therefore pwm signal is had no effect.When pwm signal was closed, NMOS pipe M2 conducting bled off the electric charge in the capacitor C 1.When load short circuits, this moment, PMOS pipe M1 opened, at this moment Vloadup voltage will charge to capacitor C 1, when charging voltage during greater than the magnitude of voltage set, inverter INV1 overturns, output low level, the output Y of second selector SEL2 and third selector SEL3 all exports the signal of the second input B: second selector SEL2 output supply voltage VDD wherein, manage M2 with NMOS and turn-off and make PMOS pipe M1 to continue conducting; Third selector SEL3 output low level makes first selector SEL1 output low level, thereby NMOS power switch pipe M3 is turn-offed, and in time protects drive circuit to be unlikely to be burnt.
Execution mode two (as shown in Figure 4):
Current deep constant-current output driving circuit with load short circuit protection function comprises driver element and load short circuits protected location.
Driver element is made up of an operational amplifier OP1, resistance R 1, resistance R 2, first selector SEL1 and NMOS power switch pipe M3; The substrate ground connection of NMOS power switch pipe M3, its source electrode is by resistance R 1 ground connection, and its grid meets the selection signal output part Y of first selector SEL1; Second of first selector SEL1 selects signal input part B by resistance R 2 ground connection, and first of first selector SEL1 selects signal input part A to connect the output of operational amplifier OP1; When the first selector selecting side was high level, its first selection signal input part A linked to each other with selecting signal output part Y; When the first selector selecting side was low level, its second selection signal input part B linked to each other with selecting signal output part Y; The external reference voltage Vref of the positive input terminal of operational amplifier OP1, its negative input end connects the source electrode of NMOS power switch pipe M3.
The load short circuits protected location is made up of sample circuit, comparison circuit and control signal output/breaking circuit: described sample circuit manages M1, NMOS pipe M2 by NMOS and capacitor C 1 is formed; Described comparison circuit is made of the first inverter INV1; Described control signal output/breaking circuit is made up of the second inverter INV2 and second selector SEL2, third selector SEL3.Second selector SEL2 is identical with the structure of third selector SEL3: when promptly selecting side S is high level first input end A is linked to each other with output Y, then the second input B is linked to each other with output Y if instead select when end S is low level.The drain electrode of NMOS pipe M1 connects the drain electrode of NMOS power switch pipe M3 in the driver element, and the source electrode of NMOS pipe M1 is by capacitor C 1 ground connection, and the grid of NMOS pipe M1 meets the input of the second inverter INV2 and the output Y of second selector SEL2; The source ground of NMOS pipe M2, its drain electrode connect the source electrode of NMOS pipe M1 and the input of the first inverter INV1; The selecting side S of the output termination second selector SEL2 of the first inverter INV1 and the selecting side S of third selector SEL3; First of second selector SEL2 selects input A and third selector SEL3 first to select input A to meet the drive control signal PWM of NMOS power switch pipe M3 in the driver element, second of second selector SEL2 selects input B to meet supply voltage VDD, second of third selector SEL3 selects input B by resistance R 3 ground connection, the output Y of second selector SEL2 connects the input of the second inverter INV1, and the output Y of third selector SEL3 meets the selecting side S of first selector in the driver element.
When technique scheme was specifically used, load (as LED) was connected between the drain electrode and load voltage Vloadup of NMOS power switch pipe M3.When the load operate as normal; the output control signal PWM_OUT of the control signal output ends of load short circuits protected location is exactly the control signal PWM of NMOS power switch pipe M3: when PWM is that high level is when opening NMOS power switch pipe M3; NMOS pipe M1 conducting; charging voltage to capacitor C 1 is that Vloadup deducts the pressure drop in the load; do not reach the comparative voltage of comparison circuit, therefore pwm signal is had no effect.When pwm signal was closed, NMOS pipe M2 conducting bled off the electric charge in the capacitor C 1.When load short circuits, this moment, NMOS pipe M1 opened, at this moment Vloadup voltage will charge to capacitor C 1, when charging voltage during greater than the magnitude of voltage set, inverter INV1 overturns, output low level, the output Y of second selector SEL2 and third selector SEL3 all exports the signal of the second input B: second selector SEL2 output supply voltage VDD wherein, manage M2 with NMOS and turn-off and make NMOS pipe M1 to continue conducting; Third selector SEL3 output low level makes first selector SEL1 output low level, thereby NMOS power switch pipe M3 is turn-offed, and in time protects drive circuit to be unlikely to be burnt.
Execution mode three (as shown in Figure 5):
Current deep constant-current output driving circuit with load short circuit protection function comprises driver element and load short circuits protected location.
Driver element is made up of an operational amplifier OP1, resistance R 1, resistance R 2, first selector SEL1 and NMOS power switch pipe M3; The substrate ground connection of NMOS power switch pipe M3, its source electrode is by resistance R 1 ground connection, and its grid meets the selection signal output part Y of first selector SEL1; Second of first selector SEL1 selects signal input part B by resistance R 2 ground connection, and first of first selector SEL1 selects signal input part A to connect the output of operational amplifier OP1; When the first selector selecting side was high level, its first selection signal input part A linked to each other with selecting signal output part Y; When the first selector selecting side was low level, its second selection signal input part B linked to each other with selecting signal output part Y; The external reference voltage Vref of the positive input terminal of operational amplifier OP1, its negative input end connects the source electrode of NMOS power switch pipe M3.
The load short circuits protected location is made up of sample circuit, comparison circuit and control signal output/breaking circuit: described sample circuit manages M1, PMOS pipe M2 by PMOS and capacitor C 1 is formed; Described comparison circuit is made of the first inverter INV1; Described control signal output/breaking circuit is made up of the second inverter INV2 and second selector SEL2, third selector SEL3.Second selector SEL2 is identical with the structure of third selector SEL3: when promptly selecting side S is high level first input end A is linked to each other with output Y, then the second input B is linked to each other with output Y if instead select when end S is low level.The source electrode of PMOS pipe M1 connects the drain electrode of NMOS power switch pipe M3 in the driver element, and the drain electrode of PMOS pipe M1 is by capacitor C 1 ground connection, and the grid of PMOS pipe M1 connects the output of the second inverter INV2; The grounded drain of PMOS pipe M2, its source electrode connect the drain electrode of PMOS pipe M1 and the input of the first inverter INV1; The selecting side S of the output termination second selector SEL2 of the first inverter INV1 and the selecting side S of third selector SEL3; First of second selector SEL2 selects input A and third selector SEL3 first to select input A to meet the drive control signal PWM of NMOS power switch pipe M3 in the driver element, second of second selector SEL2 selects input B to meet supply voltage VDD, second of third selector SEL3 selects input B by resistance R 3 ground connection, the output Y of second selector SEL2 connects the input of the second inverter INV1 and the grid of PMOS pipe M2, and the output Y of third selector SEL3 meets the selecting side S of first selector in the driver element.
When technique scheme was specifically used, load (as LED) was connected between the drain electrode and load voltage Vloadup of NMOS power switch pipe M3.When the load operate as normal; the output control signal PWM_OUT of the control signal output ends of load short circuits protected location is exactly the control signal PWM of NMOS power switch pipe M3: when PWM is that high level is when opening NMOS power switch pipe M3; PMOS pipe M1 conducting; charging voltage to capacitor C 1 is that Vloadup deducts the pressure drop in the load; do not reach the comparative voltage of comparison circuit, therefore pwm signal is had no effect.When pwm signal was closed, PMOS pipe M2 conducting bled off the electric charge in the capacitor C 1.When load short circuits, this moment, PMOS pipe M1 opened, at this moment Vloadup voltage will charge to capacitor C 1, when charging voltage during greater than the magnitude of voltage set, inverter INV1 overturns, output low level, the output Y of second selector SEL2 and third selector SEL3 all exports the signal of the second input B: second selector SEL2 output supply voltage VDD wherein, manage M2 with PMOS and turn-off and make PMOS pipe M1 to continue conducting; Third selector SEL3 output low level makes first selector SEL1 output low level, thereby NMOS power switch pipe M3 is turn-offed, and in time protects drive circuit to be unlikely to be burnt.
Execution mode four (as shown in Figure 6):
Current deep constant-current output driving circuit with load short circuit protection function comprises driver element and load short circuits protected location.
Driver element is made up of an operational amplifier OP1, resistance R 1, resistance R 2, first selector SEL1 and NMOS power switch pipe M3; The substrate ground connection of NMOS power switch pipe M3, its source electrode is by resistance R 1 ground connection, and its grid meets the selection signal output part Y of first selector SEL1; Second of first selector SEL1 selects signal input part B by resistance R 2 ground connection, and first of first selector SEL1 selects signal input part A to connect the output of operational amplifier OP1; When the first selector selecting side was high level, its first selection signal input part A linked to each other with selecting signal output part Y; When the first selector selecting side was low level, its second selection signal input part B linked to each other with selecting signal output part Y; The external reference voltage Vref of the positive input terminal of operational amplifier OP1, its negative input end connects the source electrode of NMOS power switch pipe M3.
The load short circuits protected location is made up of sample circuit, comparison circuit and control signal output/breaking circuit: described sample circuit manages M1, NMOS pipe M2 by PMOS and capacitor C 1 is formed; Described comparison circuit is made of a comparator; Described control signal output/breaking circuit is made up of the second inverter INV2 and second selector SEL2, third selector SEL3.Second selector SEL2 is identical with the structure of third selector SEL3: when promptly selecting side S is high level first input end A is linked to each other with output Y, then the second input B is linked to each other with output Y if instead select when end S is low level.The source electrode of PMOS pipe M1 connects the drain electrode of NMOS power switch pipe M3 in the driver element, and the drain electrode of PMOS pipe M1 is by capacitor C 1 ground connection, and the grid of PMOS pipe M1 connects the output of the second inverter INV2 and the grid of NMOS pipe M2; The source ground of NMOS pipe M2, its drain electrode connect the drain electrode of PMOS pipe M1 and the positive input terminal of comparator; The negative input end of comparator connects reference voltage Vref; The selecting side S of the output termination second selector SEL2 of comparator and the selecting side S of third selector SEL3; First of second selector SEL2 selects input A and third selector SEL3 first to select input A to meet the drive control signal PWM of NMOS power switch pipe M3 in the driver element, second of second selector SEL2 selects input B to meet supply voltage VDD, second of third selector SEL3 selects input B by resistance R 3 ground connection, the output Y of second selector SEL2 connects the input of the second inverter INV1, and the output Y of third selector SEL3 meets the selecting side S of first selector in the driver element.
When technique scheme was specifically used, load (as LED) was connected between the drain electrode and load voltage Vloadup of NMOS power switch pipe M3.When the load operate as normal; the output control signal PWM_OUT of the control signal output ends of load short circuits protected location is exactly the control signal PWM of NMOS power switch pipe M3: when PWM is that high level is when opening NMOS power switch pipe M3; PMOS pipe M1 conducting; charging voltage to capacitor C 1 is that Vloadup deducts the pressure drop in the load; do not reach the comparative voltage of comparison circuit, therefore pwm signal is had no effect.When pwm signal was closed, NMOS pipe M2 conducting bled off the electric charge in the capacitor C 1.When load short circuits, this moment, PMOS pipe M1 opened, at this moment Vloadup voltage will charge to capacitor C 1, when charging voltage during greater than the magnitude of voltage set, inverter INV1 overturns, output low level, the output Y of second selector SEL2 and third selector SEL3 all exports the signal of the second input B: second selector SEL2 output supply voltage VDD wherein, manage M2 with NMOS and turn-off and make PMOS pipe M1 to continue conducting; Third selector SEL3 output low level makes first selector SEL1 output low level, thereby NMOS power switch pipe M3 is turn-offed, and in time protects drive circuit to be unlikely to be burnt.
Execution mode five (as shown in Figure 7):
Current deep constant-current output driving circuit with load short circuit protection function comprises driver element and load short circuits protected location.
Driver element is made up of an operational amplifier OP1, resistance R 1, resistance R 2, first selector SEL1 and NMOS power switch pipe M3; The substrate ground connection of NMOS power switch pipe M3, its source electrode is by resistance R 1 ground connection, and its grid meets the selection signal output part Y of first selector SEL1; Second of first selector SEL1 selects signal input part B by resistance R 2 ground connection, and first of first selector SEL1 selects signal input part A to connect the output of operational amplifier OP1; When the first selector selecting side was high level, its first selection signal input part A linked to each other with selecting signal output part Y; When the first selector selecting side was low level, its second selection signal input part B linked to each other with selecting signal output part Y; The external reference voltage Vref of the positive input terminal of operational amplifier OP1, its negative input end connects the source electrode of NMOS power switch pipe M3.
The load short circuits protected location is made up of sample circuit, comparison circuit and control signal output/breaking circuit: described sample circuit manages M1, NMOS pipe M2 by PMOS and capacitor C 1, capacitor C 2 are formed; Described comparison circuit is made of the first inverter INV1; Described control signal output/breaking circuit is made up of the second inverter INV2 and second selector SEL2, third selector SEL3.Second selector SEL2 is identical with the structure of third selector SEL3: when promptly selecting side S is high level first input end A is linked to each other with output Y, then the second input B is linked to each other with output Y if instead select when end S is low level.The source electrode of PMOS pipe M1 connects the drain electrode of NMOS power switch pipe M3 in the driver element, and the drain electrode of PMOS pipe M1 is successively by capacitor C 2 and capacitor C 1 back ground connection, and the grid of PMOS pipe M1 connects the output of the second inverter INV2 and the grid of NMOS pipe M2; The source ground of NMOS pipe M2, its drain electrode connects the tie point of capacitor C 1, capacitor C 2 and the input of the first inverter INV1; The selecting side S of the output termination second selector SEL2 of the first inverter INV1 and the selecting side S of third selector SEL3; First of second selector SEL2 selects input A and third selector SEL3 first to select input A to meet the drive control signal PWM of NMOS power switch pipe M3 in the driver element, second of second selector SEL2 selects input B to meet supply voltage VDD, second of third selector SEL3 selects input B by resistance R 3 ground connection, the output Y of second selector SEL2 connects the input of the second inverter INV1, and the output Y of third selector SEL3 meets the selecting side S of first selector in the driver element.
When technique scheme was specifically used, load (as LED) was connected between the drain electrode and load voltage Vloadup of NMOS power switch pipe M3.Its operation principle is similar to the operation principle of execution mode one, just connects the form of comparative voltage from the tie point of capacitor C 1 and capacitor C 2, can further increase the flexibility of circuit application.
Claims (5)
1, the current deep constant-current output driving circuit that has load short circuit protection function comprises driver element and load short circuits protected location; Described driver element is made up of an operational amplifier, resistance R 1, resistance R 2, first selector and NMOS power switch pipe M3; The substrate ground connection of NMOS power switch pipe M3, its source electrode is by resistance R 1 ground connection, and its grid connects the selection signal output part of first selector; Second of first selector selects signal input part by resistance R 2 ground connection, and first of first selector selects signal input part to connect the output of operational amplifier; When the first selector selecting side was high level, its first selection signal input part linked to each other with selecting signal output part; When the first selector selecting side was low level, its second selection signal input part linked to each other with selecting signal output part; The external reference voltage Vref of the positive input terminal of operational amplifier, its negative input end connects the source electrode of NMOS power switch pipe M3;
Described load short circuits protected location is made up of sample circuit, comparison circuit and control signal output/breaking circuit: described sample circuit manages M1, NMOS pipe M2 by PMOS and capacitor C 1 is formed; Described comparison circuit is made of first inverter; Described control signal output/breaking circuit is made up of second inverter and second selector, third selector; The structure of second selector and third selector is identical: when promptly the selecting side is high level first input end is linked to each other with output, then second input is linked to each other with output if instead select when end is low level; The source electrode of PMOS pipe M1 connects the drain electrode of NMOS power switch pipe M3 in the driver element, and the drain electrode of PMOS pipe M1 is by capacitor C 1 ground connection, and the grid of PMOS pipe M1 connects the output of second inverter and the grid of NMOS pipe M2; The source ground of NMOS pipe M2, its drain electrode connect the drain electrode of PMOS pipe M1 and the input of first inverter; The selecting side of the output termination second selector of first inverter and the selecting side of third selector; First of second selector selects input and third selector first to select the drive control signal PWM of NMOS power switch pipe M3 in the input termination driver element, second of second selector is selected input termination supply voltage VDD, second of third selector selects input by resistance R 3 ground connection, the input of output termination second inverter of second selector, the selecting side of first selector in the output termination driver element of third selector.
2, the current deep constant-current output driving circuit that has load short circuit protection function comprises driver element and load short circuits protected location; Described driver element is made up of an operational amplifier, resistance R 1, resistance R 2, first selector and NMOS power switch pipe M3; The substrate ground connection of NMOS power switch pipe M3, its source electrode is by resistance R 1 ground connection, and its grid connects the selection signal output part of first selector; Second of first selector selects signal input part by resistance R 2 ground connection, and first of first selector selects signal input part to connect the output of operational amplifier; When the first selector selecting side was high level, its first selection signal input part linked to each other with selecting signal output part; When the first selector selecting side was low level, its second selection signal input part linked to each other with selecting signal output part; The external reference voltage Vref of the positive input terminal of operational amplifier, its negative input end connects the source electrode of NMOS power switch pipe M3;
Described load short circuits protected location is made up of sample circuit, comparison circuit and control signal output/breaking circuit: described sample circuit manages M1, NMOS pipe M2 by NMOS and capacitor C 1 is formed; Described comparison circuit is made of first inverter; Described control signal output/breaking circuit is made up of second inverter and second selector, third selector; The structure of second selector and third selector is identical: when promptly the selecting side is high level first input end is linked to each other with output, then second input is linked to each other with output if instead select when end is low level; The drain electrode of NMOS pipe M1 connects the drain electrode of NMOS power switch pipe M3 in the driver element, and the source electrode of NMOS pipe M1 is by capacitor C 1 ground connection, and the grid of NMOS pipe M1 connects the input of second inverter and the output of second selector; The source ground of NMOS pipe M2, its drain electrode connect the source electrode of NMOS pipe M1 and the input of first inverter; The selecting side of the output termination second selector of first inverter and the selecting side of third selector; First of second selector selects input and third selector first to select the drive control signal PWM of NMOS power switch pipe M3 in the input termination driver element, second of second selector is selected input termination supply voltage VDD, second of third selector selects input by resistance R 3 ground connection, the input of output termination second inverter of second selector, the selecting side of first selector in the output termination driver element of third selector.
3, the current deep constant-current output driving circuit that has load short circuit protection function comprises driver element and load short circuits protected location; Driver element is made up of an operational amplifier, resistance R 1, resistance R 2, first selector and NMOS power switch pipe M3; The substrate ground connection of NMOS power switch pipe M3, its source electrode is by resistance R 1 ground connection, and its grid connects the selection signal output part of first selector; Second of first selector selects signal input part by resistance R 2 ground connection, and first of first selector selects signal input part to connect the output of operational amplifier; When the first selector selecting side was high level, its first selection signal input part linked to each other with selecting signal output part; When the first selector selecting side was low level, its second selection signal input part linked to each other with selecting signal output part; The external reference voltage Vref of the positive input terminal of operational amplifier, its negative input end connects the source electrode of NMOS power switch pipe M3;
The load short circuits protected location is made up of sample circuit, comparison circuit and control signal output/breaking circuit: described sample circuit manages M1, PMOS pipe M2 by PMOS and capacitor C 1 is formed; Described comparison circuit is made of first inverter; Described control signal output/breaking circuit is made up of second inverter and second selector, third selector; The structure of second selector and third selector is identical: when promptly the selecting side is high level first input end is linked to each other with output, then second input is linked to each other with output if instead select when end is low level; The source electrode of PMOS pipe M1 connects the drain electrode of NMOS power switch pipe M3 in the driver element, and the drain electrode of PMOS pipe M1 is by capacitor C 1 ground connection, and the grid of PMOS pipe M1 connects the output of second inverter; The grounded drain of PMOS pipe M2, its source electrode connect the drain electrode of PMOS pipe M1 and the input of first inverter; The selecting side of the output termination second selector of first inverter and the selecting side of third selector; First of second selector selects input and third selector first to select the drive control signal PWM of NMOS power switch pipe M3 in the input termination driver element, second of second selector is selected input termination supply voltage VDD, second of third selector selects input by resistance R 3 ground connection, the grid of the input of output termination second inverter of second selector and PMOS pipe M2, the selecting side of first selector in the output termination driver element of third selector.
4, the current deep constant-current output driving circuit that has load short circuit protection function comprises driver element and load short circuits protected location; Affiliated driver element is made up of an operational amplifier, resistance R 1, resistance R 2, first selector and NMOS power switch pipe M3; The substrate ground connection of NMOS power switch pipe M3, its source electrode is by resistance R 1 ground connection, and its grid connects the selection signal output part of first selector; Second of first selector selects signal input part by resistance R 2 ground connection, and first of first selector selects signal input part to connect the output of operational amplifier; When the first selector selecting side was high level, its first selection signal input part linked to each other with selecting signal output part; When the first selector selecting side was low level, its second selection signal input part linked to each other with selecting signal output part; The external reference voltage Vref of the positive input terminal of operational amplifier, its negative input end connects the source electrode of NMOS power switch pipe M3;
Described load short circuits protected location is made up of sample circuit, comparison circuit and control signal output/breaking circuit: described sample circuit manages M1, NMOS pipe M2 by PMOS and capacitor C 1 is formed; Described comparison circuit is made of a comparator; Described control signal output/breaking circuit is made up of second inverter and second selector, third selector; The structure of second selector and third selector is identical: when promptly the selecting side is high level first input end is linked to each other with output, then second input is linked to each other with output if instead select when end is low level; The source electrode of PMOS pipe M1 connects the drain electrode of NMOS power switch pipe M3 in the driver element, and the drain electrode of PMOS pipe M1 is by capacitor C 1 ground connection, and the grid of PMOS pipe M1 connects the output of second inverter and the grid of NMOS pipe M2; The source ground of NMOS pipe M2, its drain electrode connect the drain electrode of PMOS pipe M1 and the positive input terminal of comparator; The negative input end of comparator connects reference voltage Vref; The selecting side of the output termination second selector of comparator and the selecting side of third selector; First of second selector selects input and third selector first to select the drive control signal PWM of NMOS power switch pipe M3 in the input termination driver element, second of second selector is selected input termination supply voltage VDD, second of third selector selects input by resistance R 3 ground connection, the input of output termination second inverter of second selector, the selecting side of first selector in the output termination driver element of third selector.
5, the current deep constant-current output driving circuit that has load short circuit protection function comprises driver element and load short circuits protected location; Described driver element is made up of an operational amplifier, resistance R 1, resistance R 2, first selector and NMOS power switch pipe M3; The substrate ground connection of NMOS power switch pipe M3, its source electrode is by resistance R 1 ground connection, and its grid connects the selection signal output part of first selector; Second of first selector selects signal input part by resistance R 2 ground connection, and first of first selector selects signal input part to connect the output of operational amplifier; When the first selector selecting side was high level, its first selection signal input part linked to each other with selecting signal output part; When the first selector selecting side was low level, its second selection signal input part linked to each other with selecting signal output part; The external reference voltage Vref of the positive input terminal of operational amplifier, its negative input end connects the source electrode of NMOS power switch pipe M3;
Described load short circuits protected location is made up of sample circuit, comparison circuit and control signal output/breaking circuit: described sample circuit manages M1, NMOS pipe M2 by PMOS and capacitor C 1, capacitor C 2 are formed; Described comparison circuit is made of first inverter; Described control signal output/breaking circuit is made up of second inverter and second selector, third selector; The structure of second selector and third selector is identical: when promptly the selecting side is high level first input end is linked to each other with output, then second input is linked to each other with output if instead select when end is low level; The source electrode of PMOS pipe M1 connects the drain electrode of NMOS power switch pipe M3 in the driver element, and the drain electrode of PMOS pipe M1 is successively by capacitor C 2 and capacitor C 1 back ground connection, and the grid of PMOS pipe M1 connects the output of second inverter and the grid of NMOS pipe M2; The source ground of NMOS pipe M2, its drain electrode connects the tie point of capacitor C 1, capacitor C 2 and the input of first inverter; The selecting side of the output termination second selector of first inverter and the selecting side of third selector; First of second selector selects input and third selector first to select the drive control signal PWM of NMOS power switch pipe M3 in the input termination driver element, second of second selector is selected input termination supply voltage VDD, second of third selector selects input by resistance R 3 ground connection, the input of output termination second inverter of second selector, the selecting side of first selector in the output termination driver element of third selector.
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| CNB2008100456875A CN100570978C (en) | 2008-07-30 | 2008-07-30 | Current deep constant-current output driving circuit with load short circuit protection function |
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| CNB2008100456875A CN100570978C (en) | 2008-07-30 | 2008-07-30 | Current deep constant-current output driving circuit with load short circuit protection function |
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| CN101330203A true CN101330203A (en) | 2008-12-24 |
| CN100570978C CN100570978C (en) | 2009-12-16 |
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