CN200997700Y

CN200997700Y - Large-power driving chip of LED light

Info

Publication number: CN200997700Y
Application number: CNU2007200173631U
Authority: CN
Inventors: 李江淮
Original assignee: Individual
Current assignee: Leedarson Green Lighting Co Ltd
Priority date: 2007-01-09
Filing date: 2007-01-09
Publication date: 2007-12-26
Anticipated expiration: 2017-01-09

Abstract

A LED lamp high-power drive chip is characterized in that a VCC power end is connected with a serial R1 and R2 sampling resistance through a high-voltage current source, and a MOSFET tube drain electrode, of which the other end of the sampling resistance is a common ground terminal GND, and the MOSFET tube source electrode and the common ground terminal GND are connected with Rf feedback resistance; a MOSFET tube grid electrode is connected with a PWM pulse-width modulator; N1 and N2 two-stage comparators are connected in series between the common contact of the R1 and R2 sampling resistance and the input terminal of the PWM pulse-width modulator, R3 overcurrent testing resistance is connected between a reversed phase end of the N1 and the MOSFET tube source electrode, and an in-phase end of the N2 is connected with an overheat protective circuit.

Description

LED lamp high-power driving chip

Technical field

The utility model relates to a kind of IC integrated circuit, particularly illuminating LED lamp high-power driving chip.

Background technology

Along with new material, new technology and The application of new technique, the LED illuminating lamp will enter the average family lighting field, though great power LED can't replace traditional incandescent lamp now on a large scale, it is being widely used aspect indoor and outdoor decoration, the special lighting; The high-power LED illuminating lamp is generally connected to form by several LED light-emitting diode series connection, the LED light-emitting diode luminance is to be determined by the electric current that passes through, for keeping light even and brightness is constant, all electric currents that flow through LED remain unchanged, this needs very high driving voltage, LED current unevenness weighing apparatus can shorten the useful life of LED, thereby needs to use the constant-current source driving LED, and the LED drive IC is transformed to constant-current source to general AC power in fact exactly; Great power LED drive IC working temperature is too high can to exert an influence to IC internal circuit and peripheral operating circuit thereof, the useful life of LED lamp and safe in utilization also can be influenced, thereby must design driven IC overheat protector function.

The utility model content

For addressing the above problem, the utility model is intended to propose a kind of LED lamp high-power driving chip with constant current output and overheat protector function.

The technical scheme that the invention for solving the technical problem adopted is: LED lamp high-power driving chip, it is characterized in that: VCC power end one tunnel is connected through R1, the R2 sampling resistor of high-tension current source and series connection, the sampling resistor other end is common GND, another road connects the drain electrode of MOSFET pipe, and MOSFET pipe source electrode and common GND are connected with the Rf feedback resistance; The MOSFET tube grid is connected with the PWM pulse width modulator; be in series with N1, N2 two stage comparator between R1, R2 sampling resistor points of common connection and the PWM pulse width modulator input; be connected with R3 over-current detection resistance between the end of oppisite phase of N1 and MOSFET pipe source electrode, the in-phase end of N2 is connected with overheating protection circuit.

The Rf feedback resistance that MOSFET pipe source electrode is connected with common GND is not encapsulated in the chip, draw an output VBF by MOSFET pipe source electrode, chip is three end chips, the external circuital current that makes things convenient for of Rf feedback resistance is controlled, make its peripheral circuit expansion have greater flexibility, the utility model preferentially adopts three end chips; The Rf feedback resistance that MOSFET pipe source electrode is connected with common GND is encapsulated in the chip, and chip is the two ends chip, and its output current intensity is a fixed value, can't adjust.

The beneficial effects of the utility model are: utilize the grid current size of the FEEDBACK CONTROL of PWM pulse width modulator being regulated the MOSFET power switch pipe, promptly adjust the duty of ratio size, control MOSFET pipe turn-offs, and realizes the output of pulsewidth power signal, for the LED lamp provides constant drive current; When this novel temperature surpasses the overheating protection circuit set point; overheating protection circuit is exported a low level; the N2 comparator is exported a low level; the pulse duty factor of PWM output is reduced; reduce the ON time of metal-oxide-semiconductor; thereby reduce output current, reach and reduce temperature, play the effect of overtemperature protection.

Description of drawings

Fig. 1 is the utility model three end chip internal circuit diagrams;

Fig. 2 is the utility model two ends chip internal circuit diagrams;

Fig. 3 is the embodiment circuit diagram of the utility model three end chips and peripheral circuit driving LED lamp.

Among the figure: 1. chip; 2.MOSFET pipe; 3.PWM pulse width modulator; 4. comparator; 5. overheating protection circuit; 6. sampling resistor; 7. over-current detection resistance; 8. feedback resistance; 9. peripheral circuit; 10.LED lamp.

Embodiment

Below in conjunction with drawings and Examples the utility model is further specified.

LED lamp 10 high-power driving chips 1 as shown in Figure 1, VCC power end one tunnel is connected through R1, the R2 sampling resistor 6 of high-tension current source and series connection, voltage takes out the in-phase input end that reference voltage offers comparator 4N1 through R1, R2 dividing potential drop, and sampling resistor 6 other ends are common GND; Another road connects 2 drain electrodes of MOSFET pipe; MOSFET manages 2 grids and is connected with PWM pulse width modulator 3; be in series with N1, N2 two stage comparator 4 between R1, R2 sampling resistor 6 points of common connection and PWM pulse width modulator 3 inputs; the end of oppisite phase of N1 and MOSFET manage and are connected with R3 over-current detection resistance 7 between 2 source electrodes, and the in-phase end of N2 is connected with overheating protection circuit 5.MOSFET manages 2 source electrodes and common GND is connected with Rf feedback resistance 8, and from the pipe source electrode draw an end pin VBF, then chip 1 is three end chips 1, make its peripheral circuit 9 expansions have greater flexibility, convenient adjustment design for chip output current, the utility model preferentially adopts three end chips 1.As shown in Figure 2, MOSFET manages the Rf feedback resistance 8 that 2 source electrodes are connected with common GND and is encapsulated in the chip, and chip is the two ends chip, and its output current intensity is a fixed value.

As shown in Figure 3, the utility model uses three end chips 1 to connect peripheral circuit 9 driving LED lamps 10 to be example, connect alternating current after, alternating current exports L2 to through DB bridge rectifier, L1, C1, C2 filtering, and being loaded on the VCC power end of chip 1, LED lamp 10 is connected in series through diode and L1; Chip 1 start-up course: voltage is added in VCC end, provides an operating voltage to the discharge circuit and the PWM of inside, because just built-in MOSFET pipe 2 can not conducting during making alive, electric current I o can not reach the requirement of setting, and Io＜350mA.This moment Vr＜Va, high level of first order amplifier N1 comparator 4 outputs, this moment is because overheating protection circuit 5 temperature when circuit just starts is very low, be about room temperature, second amplifier N2 comparator 4 also exported a high level, gives modulation voltage of pwm circuit, changes the duty ratio of pwm pulse, make MOSFET manage 2 conductings, export an electric current; Constant current principle: when Io＜350mA; Vrf＜Va; this voltage offers the end of oppisite phase of first order amplifier N1 comparator 4 through resistance; export a high level; when if this moment, ambient temperature was lower than the temperature of overheating protection circuit 5 settings; second level amplifier N2 comparator 4 also is high level of output, offers the ON time that modulation voltage of pwm circuit increases the duty ratio lengthening metal-oxide-semiconductor of pwm pulse, improves output current.When Io＞350mA, Vrf＞Va, this moment, the output level of two stage amplifer was opposite with Io＜350mA, exported a low level, and the modulated terminal that is added in PWM reduces the duty ratio of PWM, reduces MOSFET and manages 2 ON time and reduce output current.The overheat protector principle: the circuit set temperature value is 75 ℃.When temperature surpasses set point, low level of overheating protection circuit 5 outputs, thus make second level amplifier N2 comparator 4 also export a low level; the duty ratio of pwm circuit output is reduced; reduce the ON time of MOSFET pipe 2, thereby reduce output current, reach and reduce temperature.

The constant 350mA of the utility model chip 1 output current ± 10%, operating ambient temperature-25 ℃～85 ℃.Little power consumption; has overheat protector; thereby avoid circuit itself and peripheral operating circuit thereof being exerted an influence because of temperature rise is too high; guarantee the constant and temperature rise amplitude of the operating current of LED lamp 10 to be controlled within the setting range and prolong its useful life; the utility model chip 1 internal structure is simply compact, has the comparison application prospects in the drive circuit field of high-power LED lamp 10.

Claims

1.LED lamp high-power driving chip, it is characterized in that: VCC power end one tunnel is connected through R1, the R2 sampling resistor of high-tension current source and series connection, the sampling resistor other end is common GND, another road connects the drain electrode of MOSFET pipe, and MOSFET pipe source electrode and common GND are connected with the Rf feedback resistance; The MOSFET tube grid is connected with the PWM pulse width modulator; be in series with N1, N2 two stage comparator between R1, R2 sampling resistor points of common connection and the PWM pulse width modulator input; be connected with R3 over-current detection resistance between the end of oppisite phase of N1 and MOSFET pipe source electrode, the in-phase end of N2 is connected with overheating protection circuit.

2. LED lamp high-power driving chip according to claim 1 is characterized in that: the Rf feedback resistance that MOSFET pipe source electrode is connected with common GND is not encapsulated in the chip, draws an output VBF by MOSFET pipe source electrode, and chip is three end chips.

3. LED lamp high-power driving chip according to claim 1 is characterized in that: the Rf feedback resistance that MOSFET pipe source electrode is connected with common GND is encapsulated in the chip, and chip is the two ends chip.