CN204859646U - LED series connection parameter inspection and accusing circuit - Google Patents

Abstract

The utility model provides a LED series connection parameter inspection and accusing circuit includes steady voltage supply circuit, the detection circuitry of linear constant current circuit and LED lamp pearl cluster vf parameter, not only be applicable to single the LED magnitude determination that LED lamp pearl cluster is established ties, the uncertain condition of power vin input value, single the LED quantity that still is applicable to the series connection of LED lamp pearl cluster is uncertain, the condition that power vin input value is confirmed, follow the adjustment through the feedback, the function to the operating condition random -tracking regulation of LED lamp pearl cluster has been realized, make the electric current that flows through LED lamp pearl cluster keep invariable, thereby realize the normal stable work of LED lamp pearl cluster, the life of LED lamps and lanterns has been prolonged.

Description

A kind of LED strip connection parameter prosecution circuit

Technical field

The utility model belongs to LED constant current Driving technique field, is specifically related to a kind of LED strip connection parameter prosecution circuit realizing random-tracking regulatory function.

Background technology

LED light source as light source of new generation, just in fast development.LED is a kind of solid-state light emitting semiconductor device, it directly can be converted into light electricity, its have power consumption less, the advantage such as applicability is strong, stability is high, response time short (switching characteristic is good), environmentally safe, multicolor luminous, color developing is good, be the new light sources be worthy to be popularized.

Generally adopting at present concentrates constant current-supplying to carry out driving LED luminescence, and according to the size of LED chip size, the power of single LEDs has 0.1W, 0.2W, 0.5W, 1W etc., expect larger power, LED will be combined use in serial or parallel connection mode.Because LED is that semi-conducting material is made, there is certain discrete type, their Vf values can not be consistent, if LED is all together in series, according to the feature of series circuit, series circuit current is equal, little with the Vf value relation of single LEDs, when external input voltage is certain, when the LED quantity of LED lamp bead string series connection is different, total Vf value is different, the electric current I f value flowing through LED lamp bead string is also different, because parameter prosecution function is not with by drive circuit common at present, therefore can not realize driving the optimal tracking of LED lamp bead string, there will be when the LED quantity of LED lamp bead string series connection is many, the electric current I f value flowing through LED lamp bead string is little, cause LED luminescence more weak, light efficiency is low, when the LED quantity of LED lamp bead string series connection is few, the electric current I f value flowing through LED lamp bead string is large, and lamp pearl string can damage because long-time junction temperature is too high, shortens the useful life of LED lamp.

Therefore, for the above-mentioned defect existed in currently available technology, be necessary to study in fact, to provide a kind of scheme, solve the defect existed in prior art.

Utility model content

The purpose of this utility model is to provide a kind of LED strip connection parameter prosecution circuit realizing random-tracking regulatory function.

The purpose of this utility model realizes like this, comprise voltage stabilizing power supplying circuit, the testing circuit of linear constant current circuit and LED lamp bead string Vf parameter, described voltage stabilizing power supplying circuit comprises NPN type triode Q1, PNP type triode Q2, resistance R2, R12, R3, R4, R8, R9, R10, one end of described resistance R8 is connected with power Vcc, ground connection after the other end series resistor R9 of described resistance R8, the ungrounded end of described resistance R9 is connected with the base stage of NPN type triode Q1, the grounded emitter of described NPN type triode Q1, the collector electrode of described NPN type triode Q1 successively series resistor R2 is connected with power Vcc with after resistance R12, the base stage of described PNP type triode Q2 is connected with the non-power end that connects of resistance R12, the emitter of described PNP type triode Q2 is connected with power Vcc, the collector electrode of described PNP type triode Q2 successively series resistor R3 is connected with the positive input terminal of operational amplifier IC2 with after resistance R4, ground connection after the positive input terminal contact resistance R10 of described operational amplifier IC2,

Described linear constant current circuit comprises operational amplifier IC2, resistance R5, R11 and field effect transistor Q4, the positive input terminal of described operational amplifier IC2 connects the collector electrode of NPN type triode Q3, ground connection after the negative input end contact resistance R11 of described operational amplifier IC2, is connected with the grid of field effect transistor Q4 after the output series resistor R5 of described operational amplifier IC2;

The testing circuit of described LED lamp bead string Vf parameter comprises resistance R1, R6, R7, operational amplifier IC1 and NPN type triode Q3, one end of described resistance R1 connects power supply Vin, be connected with the drain electrode of field effect transistor Q4 after the other end serial connection LED lamp bead string DL1 of described resistance R1, the source electrode of described field effect transistor Q4 is connected with the ungrounded end of resistance R11, the positive input terminal of described operational amplifier IC1 connects power supply Vin, the negative input end of described operational amplifier IC1 is connected with the non-power end that connects of resistance R1, the output of described operational amplifier IC1 is ground connection after series resistor R6 and resistance R7 successively, the ungrounded end of described resistance R7 is connected with the base stage of NPN type triode Q3, the grounded emitter of described NPN type triode Q3.

Described voltage stabilizing power supplying circuit also comprises electric capacity C1, and one end of described electric capacity C1 is connected with the line between resistance R3 and resistance R4, the other end ground connection of described electric capacity C1.

Single LEDs quantity that the LED strip connection parameter prosecution circuit that the utility model provides is not only applicable to the series connection of LED lamp bead string is determined, the uncertain situation of power supply Vin input value, the single LEDs quantity being also applicable to the series connection of LED lamp bead string is uncertain, the situation that power supply Vin input value is determined, adjustment is followed by feedback, achieve the function that the operating state random-tracking of LED lamp bead string is regulated, make the constant current hold flowing through LED lamp bead string, thus realize the normal table work of LED lamp bead string, extend the useful life of LED lamp.

Accompanying drawing explanation

Fig. 1 is electrical block diagram of the present utility model.

Embodiment

Be further described the utility model below in conjunction with accompanying drawing, but must not be limited the utility model by any way, any change done based on the utility model training centre or improvement, all belong to protection range of the present utility model.

As shown in Figure 1, the utility model comprises voltage stabilizing power supplying circuit, the testing circuit of linear constant current circuit and LED lamp bead string Vf parameter, described voltage stabilizing power supplying circuit comprises NPN type triode Q1, PNP type triode Q2, resistance R2, R12, R3, R4, R8, R9, R10 and electric capacity C1, one end of described resistance R8 is connected with power Vcc, ground connection after the other end series resistor R9 of described resistance R8, the ungrounded end of described resistance R9 is connected with the base stage of NPN type triode Q1, the grounded emitter of described NPN type triode Q1, the collector electrode of described NPN type triode Q1 successively series resistor R2 is connected with power Vcc with after resistance R12, the base stage of described PNP type triode Q2 is connected with the non-power end that connects of resistance R12, the emitter of described PNP type triode Q2 is connected with power Vcc, the collector electrode of described PNP type triode Q2 is ground connection after series resistor R3 and electric capacity C1 successively, be connected with the positive input terminal of operational amplifier IC2 after the ungrounded end contact resistance R4 of described electric capacity C1, ground connection after the positive input terminal contact resistance R10 of described operational amplifier IC2,

Described linear constant current circuit comprises operational amplifier IC2, resistance R5, R11 and field effect transistor Q4, the positive input terminal of described operational amplifier IC2 connects the collector electrode of NPN type triode Q3, ground connection after the negative input end contact resistance R11 of described operational amplifier IC2, is connected with the grid of field effect transistor Q4 after the output series resistor R5 of described operational amplifier IC2;

The testing circuit of described LED lamp bead string Vf parameter comprises resistance R1, R6, R7, operational amplifier IC1 and NPN type triode Q3, one end of described resistance R1 connects power supply Vin, be connected with the drain electrode of field effect transistor Q4 after the other end serial connection LED lamp bead string DL1 of described resistance R1, the source electrode of described field effect transistor Q4 is connected with the ungrounded end of resistance R11, the positive input terminal of described operational amplifier IC1 connects power supply Vin, the negative input end of described operational amplifier IC1 is connected with the non-power end that connects of resistance R1, the output of described operational amplifier IC1 is ground connection after series resistor R6 and resistance R7 successively, the ungrounded end of described resistance R7 is connected with the base stage of NPN type triode Q3, the grounded emitter of described NPN type triode Q3.

The operation principle of the LED strip connection parameter prosecution circuit that the utility model provides is:

embodiment 1(single LEDs quantity of LED lamp bead string series connection is determined, power supply Vin input value is uncertain)

Single LEDs quantity of LED lamp bead string series connection is determined, now, the parameter of the resistance R1 in the testing circuit of the resistance R11 in linear constant current circuit and LED lamp bead string Vf parameter is also just fixing, and now whole circuit working is in constant current state.The constant-voltage that power Vcc provides is through resistance R8, provide stable base voltage to after resistance R9 NPN type triode Q1, the base voltage of PNP type triode Q2 is dragged down by resistance R2 by the collector current of NPN type triode Q1 stable output, the collector electrode of PNP type triode Q2 has electric current to export, through resistance R3, ground connection after resistance R4 and resistance R10, produce the positive input of stable voltage Vb as operational amplifier IC2, the concrete numerical value of voltage Vb can by changing resistance R8, the parameter of resistance R9 adjusts, electric capacity C1 is used for issuable noise signal in absorbing circuit, ensure that voltage Vb's is stable.The negative input of operational amplifier IC2 is voltage Vd, and the potential difference between its positive input voltage Vb and negative input voltage Vd determines the height of its output voltage Vc.Under normal circumstances, negative input voltage Vd is less than positive input voltage Vb, output voltage Vc is high voltage, the grid of field effect transistor Q4 is added to through resistance R5, field effect transistor Q4 conducting, have electric current I f from power supply Vin after resistance R1, LED lamp bead string DL1, field effect transistor Q4 and resistance R11 to ground, LED lamp bead string DL1 lights luminescence.Keep stable when power supply Vin inputs, that electric current I f flowing through LED lamp bead string DL1 is constant current, LED lamp bead string DL1 normal luminous; Raise when power supply Vin input is changed to voltage, that electric current I f flowing through LED lamp bead string DL1 strengthens thereupon, namely the electric current flowing through resistance R11 also strengthens, the negative input voltage Vd of operational amplifier IC2 raises, positive input voltage Vb is stable not to be become, and the positive and negative terminal voltage difference of operational amplifier IC2 reduces, and causes the output voltage Vc of operational amplifier IC2 to decline, and then causing the grid voltage of field effect transistor Q4 to decline, electric current I f declines; Otherwise, reduce when power supply Vin input is changed to voltage, that electric current I f flowing through LED lamp bead string DL1 reduces thereupon, namely the electric current flowing through resistance R11 also reduces, and the negative input voltage Vd of operational amplifier IC2 reduces, and positive input voltage Vb is stable not to be become, the positive and negative terminal voltage difference of operational amplifier IC2 increases, cause the output voltage Vc of operational amplifier IC2 to rise, and then cause the grid voltage of field effect transistor Q4 to rise, electric current I f increases; By above-mentioned feedback adjusting process, LED lamp bead string is made to can be good at adapting to the change of external power source Vin input, make the constant current hold flowing through LED lamp bead string, thus realize the normal table work of LED lamp bead string, extend the useful life of LED lamp.

embodiment 2(single LEDs quantity of LED lamp bead string series connection is uncertain, and power supply Vin input value is determined)

When power supply input Vin keeps stable, when single LEDs quantity that LED lamp bead string DL1 connects is few, its total Vf value is little, the electric current I f flowing through LED lamp bead string DL1 is large, voltage drop on resistance R1 increases, voltage Vr1 value declines, the positive input voltage of operational amplifier IC1 is much larger than its negative input voltage, the output voltage Va of operational amplifier IC1 increases, by resistance R6, resistance R7 makes the base voltage of NPN type triode Q3 rise, increase the collector current of operational amplifier Q3, thus reduce the positive input voltage Vb value of operational amplifier IC2, the output voltage Vc of operational amplifier IC2 reduces, the electric current I f flowing through LED lamp bead string DL1 is caused to reduce, in like manner, when single LEDs quantity that LED lamp bead string DL1 connects is many, its total Vf value is large, the electric current I f flowing through LED lamp bead string DL1 is little, voltage drop on resistance R1 reduces, voltage Vr1 value rises, the positive input voltage of operational amplifier IC1 far may equal its negative input voltage, the output voltage Va of operational amplifier IC1 declines, by resistance R6, resistance R7 makes the base voltage of NPN type triode Q3 decline, reduce the collector current of operational amplifier Q3, thus add the positive input voltage Vb value of operational amplifier IC2, the output voltage Vc of operational amplifier IC2 raises, the electric current I f flowing through LED lamp bead string DL1 is caused to rise.When power supply input Vin keeps stable, the change of LED lamp bead string Series Sheet LEDs quantity, reflect the change of its total forward voltage Vf value, thus cause the change flowing through the electric current I f of LED lamp bead string, the voltage drop at resistance R1 two ends also changes, by falling the detection of change to resistance R1 both end voltage, the operating state of LED strip connection parameter prosecution circuit to LED lamp bead string that the utility model provides achieves the function that random-tracking regulates, can be good at the LED lamp bead string being adapted to different serial number, ensure its normal effective work.

Claims (2)

1. a LED strip connection parameter prosecution circuit, comprises the testing circuit of voltage stabilizing power supplying circuit, linear constant current circuit and LED lamp bead string Vf parameter, it is characterized in that:

Described voltage stabilizing power supplying circuit comprises NPN type triode Q1, PNP type triode Q2, resistance R2, R12, R3, R4, R8, R9, R10, one end of described resistance R8 is connected with power Vcc, ground connection after the other end series resistor R9 of described resistance R8, the ungrounded end of described resistance R9 is connected with the base stage of NPN type triode Q1, the grounded emitter of described NPN type triode Q1, the collector electrode of described NPN type triode Q1 successively series resistor R2 is connected with power Vcc with after resistance R12, the base stage of described PNP type triode Q2 is connected with the non-power end that connects of resistance R12, the emitter of described PNP type triode Q2 is connected with power Vcc, the collector electrode of described PNP type triode Q2 successively series resistor R3 is connected with the positive input terminal of operational amplifier IC2 with after resistance R4, ground connection after the positive input terminal contact resistance R10 of described operational amplifier IC2,

Described linear constant current circuit comprises operational amplifier IC2, resistance R5, R11 and field effect transistor Q4, the positive input terminal of described operational amplifier IC2 connects the collector electrode of NPN type triode Q3, ground connection after the negative input end contact resistance R11 of described operational amplifier IC2, is connected with the grid of field effect transistor Q4 after the output series resistor R5 of described operational amplifier IC2;

The testing circuit of described LED lamp bead string Vf parameter comprises resistance R1, R6, R7, operational amplifier IC1 and NPN type triode Q3, one end of described resistance R1 connects power supply Vin, be connected with the drain electrode of field effect transistor Q4 after the other end serial connection LED lamp bead string DL1 of described resistance R1, the source electrode of described field effect transistor Q4 is connected with the ungrounded end of resistance R11, the positive input terminal of described operational amplifier IC1 connects power supply Vin, the negative input end of described operational amplifier IC1 is connected with the non-power end that connects of resistance R1, the output of described operational amplifier IC1 is ground connection after series resistor R6 and resistance R7 successively, the ungrounded end of described resistance R7 is connected with the base stage of NPN type triode Q3, the grounded emitter of described NPN type triode Q3.

2. LED strip connection parameter prosecution circuit according to claim 1, it is characterized in that: described voltage stabilizing power supplying circuit also comprises electric capacity C1, one end of described electric capacity C1 is connected with the tie point between resistance R3 and resistance R4, the other end ground connection of described electric capacity C1.