CN204559983U - A kind of LED drive chip - Google Patents
A kind of LED drive chip Download PDFInfo
- Publication number
- CN204559983U CN204559983U CN201520303425.XU CN201520303425U CN204559983U CN 204559983 U CN204559983 U CN 204559983U CN 201520303425 U CN201520303425 U CN 201520303425U CN 204559983 U CN204559983 U CN 204559983U
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- China
- Prior art keywords
- voltage
- circuit
- signal
- nmos tube
- output
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
- Y02B20/40—Control techniques providing energy savings, e.g. smart controller or presence detection
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Abstract
The utility model discloses a kind of LED drive chip.A kind of LED drive chip comprises shuts down control, band-gap reference, oscillator, error amplifier, PWM comparator, overcurrent protection comparator, current sample amplifier, control logic, power tube drive circuit and power NMOS tube.This chip has the functions such as overcurrent restriction protection, current detecting and load protection.
Description
Technical field
The utility model relates to integrated circuit technique, refers more particularly to LED drive chip.
Background technology
In order to control LED better, design a kind of LED drive chip.
Summary of the invention
The utility model aims to provide a kind of LED drive chip.
A kind of LED drive chip, comprises and shuts down control, band-gap reference, oscillator, error amplifier, PWM comparator, overcurrent protection comparator, current sample amplifier, control logic, power tube drive circuit and power NMOS tube:
The input on/off signal input part SHDN of described shutdown control circuit, output controls described control logic; When SHDN connects high level, circuit normally works; When SHDN ground connection, circuit is in closed condition, and circuit does not work;
Described band-gap reference is used for producing the bandgap voltage reference of chip internal; As the reference voltage of other circuit, the accuracy of these voltages directly affects the voltage accuracy of output;
Described pierce circuit provides internal clock frequencies, and as internal synchronizing clock;
The difference of output feedack voltage VFB and benchmark voltage VREF carries out amplifying and feeding back by described error amplifier, ensures precision of voltage regulation during stable state;
Described PWM comparator is that the voltage error signal of error amplifier output and inductive current sampled signal are compared, and exports corresponding pulse-width signal, thus controls the duty ratio of power NMOS tube, reach the object of regulation output voltage;
Described overcurrent protection comparator is when circuit has just started to start, the voltage of VFB end is very low, the output of described error amplifier is very large, such power NMOS tube can conducting always, device can be damaged like this, in order to avoid this phenomenon, the voltage signal that sampling resistor obtains is accessed the anode of described overcurrent protection comparator, thus realize controlling the duty ratio of power NMOS tube;
Described current sense amplifier is amplified by the voltage signal that sampling resistor Rsense obtains, and output and described error amplification signal are sent in described PWM comparator and compare, and realize the control to power NMOS tube;
Described control logic realizes the logic control function of system, processes, produce power tube and control signal to drive circuit control power NMOS tube operating state;
Described power tube drive circuit practical function is driving power NMOS tube.
The course of normal operation of system: when SHDN signal is high level, whole chip is started working; The difference of VFB feedback voltage and VREF produces the negative terminal of error amplification signal to described PWM comparator by described error amplifier, to represent that power NMOS tube current signal outputs to the anode of PWM comparator simultaneously, the output signal of PWM comparator controls the duty ratio of switching signal in power NMOS tube, thus reaches the object of control system output voltage.This chip has the functions such as overcurrent restriction protection, current detecting and load protection; Whole loop is one-pole system simultaneously, does not therefore need compensating circuit just can ensure the stability of system.
Accompanying drawing explanation
Fig. 1 is internal circuit diagram and the application drawing of a kind of LED drive chip of the present utility model.
Embodiment
Below in conjunction with accompanying drawing, the utility model content is further illustrated.
A kind of LED drive chip, as shown in Figure 1, comprises and shuts down control, band-gap reference, oscillator, error amplifier, PWM comparator, overcurrent protection comparator, current sample amplifier, control logic, power tube drive circuit and power NMOS tube:
The input on/off signal input part SHDN of described shutdown control circuit, output controls described control logic; When SHDN connects high level, circuit normally works; When SHDN ground connection, circuit is in closed condition, and circuit does not work;
Described band-gap reference is used for producing the bandgap voltage reference of chip internal; As the reference voltage of other circuit, the accuracy of these voltages directly affects the voltage accuracy of output;
Described pierce circuit provides internal clock frequencies, and as internal synchronizing clock;
The difference of output feedack voltage VFB and benchmark voltage VREF carries out amplifying and feeding back by described error amplifier, ensures precision of voltage regulation during stable state;
Described PWM comparator is that the voltage error signal of error amplifier output and inductive current sampled signal are compared, and exports corresponding pulse-width signal, thus controls the duty ratio of power NMOS tube, reach the object of regulation output voltage;
Described overcurrent protection comparator is when circuit has just started to start, the voltage of VFB end is very low, the output of described error amplifier is very large, such power NMOS tube can conducting always, device can be damaged like this, in order to avoid this phenomenon, the voltage signal that sampling resistor obtains is accessed the anode of described overcurrent protection comparator, thus realize controlling the duty ratio of power NMOS tube;
Described current sense amplifier is amplified by the voltage signal that sampling resistor Rsense obtains, and output and described error amplification signal are sent in described PWM comparator and compare, and realize the control to power NMOS tube;
Described control logic realizes the logic control function of system, processes, produce power tube and control signal to drive circuit control power NMOS tube operating state;
Described power tube drive circuit practical function is driving power NMOS tube.
The course of normal operation of system: when SHDN signal is high level, whole chip is started working; The difference of VFB feedback voltage and VREF produces the negative terminal of error amplification signal to described PWM comparator by described error amplifier, to represent that power NMOS tube current signal outputs to the anode of PWM comparator simultaneously, the output signal of PWM comparator controls the duty ratio of switching signal in power NMOS tube, thus reaches the object of control system output voltage.This chip has the functions such as overcurrent restriction protection, current detecting and load protection; Whole loop is one-pole system simultaneously, does not therefore need compensating circuit just can ensure the stability of system.
Claims (1)
1. a LED drive chip, is characterized in that, comprises and shuts down control, band-gap reference, oscillator, error amplifier, PWM comparator, overcurrent protection comparator, current sample amplifier, control logic, power tube drive circuit and power NMOS tube:
The input on/off signal input part SHDN of described shutdown control circuit, output controls described control logic; When SHDN connects high level, circuit normally works; When SHDN ground connection, circuit is in closed condition, and circuit does not work;
Described band-gap reference is used for producing the bandgap voltage reference of chip internal; As the reference voltage of other circuit, the accuracy of these voltages directly affects the voltage accuracy of output;
Described pierce circuit provides internal clock frequencies, and as internal synchronizing clock;
The difference of output feedack voltage VFB and benchmark voltage VREF carries out amplifying and feeding back by described error amplifier, ensures precision of voltage regulation during stable state;
Described PWM comparator is that the voltage error signal of error amplifier output and inductive current sampled signal are compared, and exports corresponding pulse-width signal, thus controls the duty ratio of power NMOS tube, reach the object of regulation output voltage;
Described overcurrent protection comparator is when circuit has just started to start, the voltage of VFB end is very low, the output of described error amplifier is very large, such power NMOS tube can conducting always, device can be damaged like this, in order to avoid this phenomenon, the voltage signal that sampling resistor obtains is accessed the anode of described overcurrent protection comparator, thus realize controlling the duty ratio of power NMOS tube;
Described current sense amplifier is amplified by the voltage signal that sampling resistor Rsense obtains, and output and described error amplification signal are sent in described PWM comparator and compare, and realize the control to power NMOS tube;
Described control logic realizes the logic control function of system, processes, produce power tube and control signal to drive circuit control power NMOS tube operating state;
Described power tube drive circuit practical function is driving power NMOS tube.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520303425.XU CN204559983U (en) | 2015-05-08 | 2015-05-08 | A kind of LED drive chip |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520303425.XU CN204559983U (en) | 2015-05-08 | 2015-05-08 | A kind of LED drive chip |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN204559983U true CN204559983U (en) | 2015-08-12 |
Family
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201520303425.XU Expired - Fee Related CN204559983U (en) | 2015-05-08 | 2015-05-08 | A kind of LED drive chip |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN204559983U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109061272A (en) * | 2018-08-30 | 2018-12-21 | 广州金升阳科技有限公司 | A kind of current detection circuit |
| CN112688674A (en) * | 2020-12-15 | 2021-04-20 | 郑州嘉晨电器有限公司 | Overcurrent protection circuit of power switch tube |
-
2015
- 2015-05-08 CN CN201520303425.XU patent/CN204559983U/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109061272A (en) * | 2018-08-30 | 2018-12-21 | 广州金升阳科技有限公司 | A kind of current detection circuit |
| CN109061272B (en) * | 2018-08-30 | 2020-08-18 | 广州金升阳科技有限公司 | Current detection circuit |
| CN112688674A (en) * | 2020-12-15 | 2021-04-20 | 郑州嘉晨电器有限公司 | Overcurrent protection circuit of power switch tube |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20150812 Termination date: 20160508 |
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| CF01 | Termination of patent right due to non-payment of annual fee |