CN202524374U - Constant current driving circuit based on PWM - Google Patents
Constant current driving circuit based on PWM Download PDFInfo
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- CN202524374U CN202524374U CN2012200869032U CN201220086903U CN202524374U CN 202524374 U CN202524374 U CN 202524374U CN 2012200869032 U CN2012200869032 U CN 2012200869032U CN 201220086903 U CN201220086903 U CN 201220086903U CN 202524374 U CN202524374 U CN 202524374U
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Abstract
The utility model discloses a constant current driving circuit based on PWM. The constant current driving circuit comprises a 555PWM waveform circuit and a LM3405 constant current driving circuit. The 555PWM waveform circuit, the LM3405 constant current driving circuit and a load are successively and electrically connected with each other. By using the circuit of the utility model, a constant current driving function can be realized. The circuit has the following advantages that: a structure is simple; a circuit volume is small; cost is low; a scope of application is wide and so on.
Description
Technical field
The utility model relates to a kind of constant-current drive circuit, specifically, relates to a kind of constant-current drive circuit based on PWM.
Background technology
Increase along with what constant-current circuit used in circuit, occurred multiple constant-current circuit structure now.But be to be that primary element is constructed constant-current circuit basically, change the size of constant current value through the change of sampled voltage with amplifier and triode or MOS transistor.Also have seldom a part adopt the constant-current circuit based on PWM, but these circuit produce PWM through MCU usually and change the duty ratio of PWM, such circuit often has complex structure, the circuit volume is big, cost is higher weak point.
The utility model content
The purpose of the utility model is to provide a kind of constant-current drive circuit based on PWM, can realize the constant-current driving function, and solved that the complex structure, circuit volume of foregoing circuit is big, cost is than problems such as height.
In order to achieve the above object; The technical scheme that the utility model adopts is: a kind of constant-current drive circuit based on PWM; Comprise 555PWM waveform circuit and LM3406 constant-current drive circuit, said 555PWM waveform circuit, LM3406 constant-current drive circuit and load are electrically connected successively.
Further, said 555PWM waveform circuit comprises 555 chip U1, resistance R 1, potentiometer R2, resistance R 3, capacitor C 1, capacitor C 2, diode D1 and diode D2; The earth terminal GND ground connection of said 555 chip U1 connects an end of capacitor C 1 and capacitor C 2 simultaneously; The low triggering end TRI of said 555 chip U1 links to each other with the negative pole of diode D1, links to each other with the positive pole of diode D2 simultaneously, and connects the other end of capacitor C 2; The output OUT output PWM waveform of said 555 chip U1 connects the LM3406 constant-current drive circuit; The reset terminal RES of said 555 chip U1 connects an end of 5V positive source and resistance R 1 simultaneously; And the other end of resistance R 1 connects an end of potentiometer R2 stiff end; The other end of potentiometer R2 stiff end connects resistance R 3, and the other end of resistance R 3 links to each other with the negative pole of diode D2; The control end CON of said 555 chip U1 is connected with an end of capacitor C 1, and the other end of capacitor C 1 is connected with the negative pole of 5V power supply, simultaneously ground connection; The high-triggering end THR of said 555 chip U1 links to each other with the positive pole of the negative pole of diode D1 and diode D2 and an end of capacitor C 2, is connected with the trigger end TRI of 555 chip U1 simultaneously; The discharge end CIS of said 555 chip U1 links to each other with the positive pole of diode D1, connects the moving contact end of potentiometer R2 simultaneously; The power input VCC of said 555 chip U1 connects the positive pole of 5V power supply, links to each other with resistance R 1 with reset terminal simultaneously.
Further, said LM3406 constant-current drive circuit comprises LM3406 chip U2, voltage-stabiliser tube D1, inductance L 1, capacitor C
IN, capacitor C
B, capacitor C
C, capacitor C
F, resistance R
ON, resistance R
SNSThe input voltage pin VIN of said LM3406 chip U2, light modulation input voltage PWM comparator input pin VINS meet power supply V
IN, while and capacitor C
IN, resistance R
ONAn end link to each other and capacitor C
INOther end ground connection, resistance R
ONThe ON time control pin RON of another termination LM3406 chip U2; The light modulation input PWM pin DIM of said LM3406 chip U2 is electrically connected with the 555PMW waveform circuit; The output pin COMP capacitor C of the error amplifier of said LM3406 chip U2
CAn end link to each other capacitor C
COther end ground connection; The bootstrapping MOSFET of said LM3406 chip U2 drives pin BOOT and capacitor C
BAn end connect and capacitor C
BThe other end be connected simultaneously with the switch pin SW of LM3406 chip U2, an end of inductance L 1, the negative pole of pressurizer D1; And the plus earth of pressurizer D1, the other end of inductance L 1 is connected with the output voltage detection pin VOUT of LM3406 chip U2 and the positive pole of load simultaneously; Switch pin SW while and the capacitor C of said LM3406 chip U2
BThe negative pole, an end of inductance L 1 of an end, pressurizer D1 link to each other; The output voltage of said LM3406 chip U2 detects pin VOUT and links to each other with the other end of inductance L 1, the positive pole of load simultaneously; The current detecting feedback pin CS of said LM3406 chip U2 connects the negative pole of load, connects resistance R simultaneously
SNSAn end, resistance R
SNSOther end ground connection; The linear output VCC of the inside 7V of said LM3406 chip U2 connects capacitor C
FAn end, capacitor C
FOther end ground connection; The grounding pin GND ground connection of said LM3406 chip U2.
The beneficial effect of the utility model is: the utility model can be realized the constant-current driving function, and has advantages such as simple in structure, that the circuit volume is little, cost is low, the scope of application is wide.
Description of drawings
Fig. 1 is the schematic diagram of the utility model based on the constant-current drive circuit of PWM;
Fig. 2 is the 555PWM waveform circuit schematic diagram of the utility model based on the constant-current drive circuit of PWM;
Fig. 3 is the LM3406 constant-current drive circuit schematic diagram of the utility model based on the constant-current drive circuit of PWM.
Embodiment
Below in conjunction with accompanying drawing the utility model is done further detailed explanation.
As shown in Figure 1, a kind of constant-current drive circuit based on PWM comprises 555PWM waveform circuit and LM3406 constant-current drive circuit, and 555PWM waveform circuit, LM3406 constant-current drive circuit and load are electrically connected successively.
As shown in Figure 2, the 555PWM waveform circuit comprises 555 chip U1, resistance R 1, potentiometer R2, resistance R 3, capacitor C 1, capacitor C 2, diode D1 and diode D2; The earth terminal GND ground connection of (1) 555 chip U1 connects an end of capacitor C 1 and capacitor C 2 simultaneously; The low triggering end TRI of (2) 555 chip U1 links to each other with the negative pole of diode D1, links to each other with the positive pole of diode D2 simultaneously, and connects the other end of capacitor C 2; The output OUT output PWM waveform of (3) 555 chip U1 connects the LM3406 constant-current drive circuit; The reset terminal RES of (4) 555 chip U1 connects an end of 5V positive source and resistance R 1 simultaneously; And the other end of resistance R 1 connects an end of potentiometer R2 stiff end; The other end of potentiometer R2 stiff end connects resistance R 3, and the other end of resistance R 3 links to each other with the negative pole of diode D2; The control end CON of (5) 555 chip U1 is connected with an end of capacitor C 1, and the other end of capacitor C 1 is connected with the negative pole of 5V power supply, simultaneously ground connection; The high-triggering end THR of (6) 555 chip U1 links to each other with the positive pole of the negative pole of diode D1 and diode D2 and an end of capacitor C 2, is connected with the trigger end TRI of 555 chip U1 simultaneously; The discharge end CIS of (7) 555 chip U1 links to each other with the positive pole of diode D1, connects the moving contact end of potentiometer R2 simultaneously; The power input VCC of (8) 555 chip U1 connects the positive pole of 5V power supply, links to each other with resistance R 1 with reset terminal simultaneously.
During the work of 555PWM waveform circuit, because the unilateal conduction characteristic of D1, D2 in the circuit makes charging and discharging circuit separately, regulator potentiometer is with regard to the duty ratio of scalable multivibrator.To capacitor C 1 charging, the charging interval is VCC through R1, D1:
TpH＝0.7R1C1
Capacitor C1 is through the discharge of the triode T among the D2, R2 and 555, and be discharge time:
TpH＝0.7R2C1
Thereby the concussion frequency is:
f＝1.43/{(R1+R2)C1}
The duty ratio of circuit output waveform is:
q(％)＝R1/(R1+R2)*100％
As shown in Figure 3, the LM3406 constant-current drive circuit comprises LM3406 chip U2, voltage-stabiliser tube D1, inductance L 1, capacitor C IN, capacitor C B, capacitor C C, capacitor C F, resistance R ON, resistance R SNS.(1) the input voltage pin VIN of LM3406 chip U2, light modulation input voltage PWM comparator input pin VINS meet power supply VIN; Link to each other with the end of capacitor C IN, resistance R ON simultaneously; And the other end ground connection of capacitor C IN, the ON time control pin RON of another termination LM3406 chip U2 of resistance R ON; (2) light modulation of LM3406 chip U2 input PWM pin DIM is electrically connected with the 555PMW waveform circuit; (3) end of the output pin COMP capacitor C C of the error amplifier of LM3406 chip U2 links to each other, the other end ground connection of capacitor C C; (4) the bootstrapping MOSFET of LM3406 chip U2 driving pin BOOT is connected with the end of capacitor C B; And the other end of capacitor C B is connected with the switch pin SW of LM3406 chip U2, an end of inductance L 1, the negative pole of pressurizer D1 simultaneously; And the plus earth of pressurizer D1, the other end of inductance L 1 is connected with the output voltage detection pin VOUT of LM3406 chip U2 and the positive pole of load simultaneously; (5) the switch pin SW of LM3406 chip U2 links to each other with the end of capacitor C B, the negative pole of pressurizer D1, an end of inductance L 1 simultaneously; (6) output voltage of LM3406 chip U2 detection pin VOUT links to each other with the other end of inductance L 1, the positive pole of load simultaneously; (7) the current detecting feedback pin CS of LM3406 chip U2 connects the negative pole of load, connects the end of resistance R SNS simultaneously, the other end ground connection of resistance R SNS; (8) the linear output VCC of the inside 7V of LM3406 chip U2 connects the end of capacitor C F, the other end ground connection of capacitor C F; (9) the grounding pin GND ground connection of LM3406 chip U2.
LM3406 possesses wide input voltage range, hangs down reference voltage, and is provided with the lowering and stabilizing blood pressure device of two-conductor line dimming function.Therefore, LM3406 is desirable constant current source of supply, and the forward current up to 1.5A is provided.In addition, this chip adopts controlled ON time (COT) structure, wherein built-in comparator and disposable startup timer, and it is different with fixed clock to start timer, the change of its change and input and output voltage is inverse relation.The LM3406 built-in chip type can be guaranteed the integrating circuit that electric current is on average exported, and when transducer adopted continuous conduction mode (CCM) operation, controlled ON time structure can be guaranteed no matter to import and how the changing of output voltage, and switching frequency all can be invariable.Therefore the output current of LM3406 is very accurate, and transient response also is exceedingly fast, and can guarantee that under condition of different switching frequency is invariable.
LM3406 has special PWM DIM pin, can accept the PWM frequency and the amplitude of relative broad range, thereby becomes very simple with the interface of external logic.The DIM function works on internal circuit when closing output driving circuit, thereby avoids restarting the delay that IC causes.
The preferred embodiment that the above is merely the utility model is not the practical range that is used for limiting the utility model; If do not break away from the spirit and the scope of the utility model, the utility model is made amendment or is equal to replacement, all should be encompassed in the middle of the protection range of the utility model claim.
Claims (3)
1. constant-current drive circuit based on PWM, it is characterized in that: comprise 555PWM waveform circuit and LM3406 constant-current drive circuit, said 555PWM waveform circuit, LM3406 constant-current drive circuit and load are electrically connected successively.
2. a kind of constant-current drive circuit based on PWM according to claim 1 is characterized in that: said 555PWM waveform circuit comprises 555 chip U1, resistance R 1, potentiometer R2, resistance R 3, capacitor C 1, capacitor C 2, diode D1 and diode D2; The earth terminal GND ground connection of said 555 chip U1 connects an end of capacitor C 1 and capacitor C 2 simultaneously; The low triggering end TRI of said 555 chip U1 links to each other with the negative pole of diode D1, links to each other with the positive pole of diode D2 simultaneously, and connects the other end of capacitor C 2; The output OUT output PWM waveform of said 555 chip U1 connects the LM3406 constant-current drive circuit; The reset terminal RES of said 555 chip U1 connects an end of 5V positive source and resistance R 1 simultaneously; And the other end of resistance R 1 connects an end of potentiometer R2 stiff end; The other end of potentiometer R2 stiff end connects resistance R 3, and the other end of resistance R 3 links to each other with the negative pole of diode D2; The control end CON of said 555 chip U1 is connected with an end of capacitor C 1, and the other end of capacitor C 1 is connected with the negative pole of 5V power supply, simultaneously ground connection; The high-triggering end THR of said 555 chip U1 links to each other with the positive pole of the negative pole of diode D1 and diode D2 and an end of capacitor C 2, is connected with the trigger end TRI of 555 chip U1 simultaneously; The discharge end CIS of said 555 chip U1 links to each other with the positive pole of diode D1, connects the moving contact end of potentiometer R2 simultaneously; The power input VCC of said 555 chip U1 connects the positive pole of 5V power supply, links to each other with resistance R 1 with reset terminal simultaneously.
3. a kind of constant-current drive circuit based on PWM according to claim 1 is characterized in that: said LM3406 constant-current drive circuit comprises LM3406 chip U2, voltage-stabiliser tube D1, inductance L 1, capacitor C
IN, capacitor C
B, capacitor C
C, capacitor C
F, resistance R
ON, resistance R
SNSThe input voltage pin VIN of said LM3406 chip U2, light modulation input voltage PWM comparator input pin VINS meet power supply V
IN, while and capacitor C
IN, resistance R
ONAn end link to each other and capacitor C
INOther end ground connection, resistance R
ONThe ON time control pin RON of another termination LM3406 chip U2; The light modulation input PWM pin DIM of said LM3406 chip U2 is electrically connected with the 555PMW waveform circuit; The output pin COMP capacitor C of the error amplifier of said LM3406 chip U2
CAn end link to each other capacitor C
COther end ground connection; The bootstrapping MOSFET of said LM3406 chip U2 drives pin BOOT and capacitor C
BAn end connect and capacitor C
BThe other end be connected simultaneously with the switch pin SW of LM3406 chip U2, an end of inductance L 1, the negative pole of pressurizer D1; And the plus earth of pressurizer D1, the other end of inductance L 1 is connected with the output voltage detection pin VOUT of LM3406 chip U2 and the positive pole of load simultaneously; Switch pin SW while and the capacitor C of said LM3406 chip U2
BThe negative pole, an end of inductance L 1 of an end, pressurizer D1 link to each other; The output voltage of said LM3406 chip U2 detects pin VOUT and links to each other with the other end of inductance L 1, the positive pole of load simultaneously; The current detecting feedback pin CS of said LM3406 chip U2 connects the negative pole of load, connects resistance R simultaneously
SNSAn end, resistance R
SNSOther end ground connection; The linear output VCC of the inside 7V of said LM3406 chip U2 connects capacitor C
FAn end, capacitor C
FOther end ground connection; The grounding pin GND ground connection of said LM3406 chip U2.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2012200869032U CN202524374U (en) | 2012-03-09 | 2012-03-09 | Constant current driving circuit based on PWM |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2012200869032U CN202524374U (en) | 2012-03-09 | 2012-03-09 | Constant current driving circuit based on PWM |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN202524374U true CN202524374U (en) | 2012-11-07 |
Family
ID=47107299
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2012200869032U Expired - Fee Related CN202524374U (en) | 2012-03-09 | 2012-03-09 | Constant current driving circuit based on PWM |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN202524374U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104039057A (en) * | 2014-06-30 | 2014-09-10 | 浙江福斯特电子科技有限公司 | Constant luminous flux LED module control circuit |
-
2012
- 2012-03-09 CN CN2012200869032U patent/CN202524374U/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104039057A (en) * | 2014-06-30 | 2014-09-10 | 浙江福斯特电子科技有限公司 | Constant luminous flux LED module control circuit |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20121107 Termination date: 20130309 |