The constant switching power supply of a kind of non-linear negative feedback big current LED
Technical field
The utility model relates to a kind of switching power supply, specifically refers to the constant switching power supply of a kind of non-linear negative feedback big current LED.
Background technology
Along with continuous progress scientific and technological at present, electronic product also brings great convenience to people are in life while function from strength to strength.Voltage stabilizing circuit is just runed and gives birth to, and traditional series connection linear regulator type voltage stabilizing circuit has the features such as stability is high, output voltage is adjustable, ripple coefficient is little, circuit is simple.But the Correctional tube of these series connection linear regulator type voltage stabilizing circuits is always operating at magnifying state, and have electric current to flow through, therefore the power consumption of its pipe is comparatively large, the efficiency of circuit is not high, generally can only reach about 30% ~ 50% always.In order to overcome above-mentioned defect, people just have developed switching mode voltage stabilizing circuit.
In switching mode voltage stabilizing circuit, surge pipe is operated on off state, pipe alternation saturated with cut-off two states in.When pipe saturation conduction, though it is large to flow through pipe current, but tube voltage drop is very little; When pipe ends, tube voltage drop is large, but the electric current flow through is close to zero.Therefore, under power output the same terms, the efficiency of switching mode voltage stabilizer coin series regulator is high, generally can reach about 80% ~ 90%.But it is comparatively large that the switching mode voltage stabilizer that current people adopt but exists ripple coefficient, when Correctional tube constantly switches between saturated and cut-off state, radio frequency interference can be produced to circuit, circuit more complicated and cost is higher.
Utility model content
The purpose of this utility model is the defect that ripple coefficient is comparatively large, radio frequency interference is serious, circuit is complicated and efficiency is not high overcoming the existence of current switching mode voltage stabilizer, provides the constant switching power supply of a kind of non-linear negative feedback big current LED.
The purpose of this utility model is achieved through the following technical solutions: the constant switching power supply of a kind of non-linear negative feedback big current LED, primarily of diode rectifier U, power amplifier P1, transformer T, voltage comparator U1, be serially connected in the switched filter circuit between the cathode output end of diode rectifier U and the in-phase end of power amplifier P1, the power output circuit be connected with the secondary coil L2 of transformer T, the transformation feedback circuit be connected with the secondary coil L3 of transformer T, the non-linear negative-feedback circuit be connected with transformation feedback circuit, input is connected with the cathode output end of diode rectifier U, output holds with the R of voltage comparator U1 the current sense amplifier circuit be connected, one end is held with the S of voltage comparator U1 and is connected, the other end is in turn through oscillator that ramp generator is connected with current sense amplifier circuit after slope equalizer M, and output is connected with the tap on the primary coil L1 of transformer T, and the sliding damper that input is connected with the output of power amplifier P1 forms, the Q end of described voltage comparator U1 is then connected with the end of oppisite phase of power amplifier P1.
Described current sense amplifier circuit is made up of current sense amplifier IP1, current sense amplifier IP2, voltage detecting amplifier A and current sense amplifier IP3; Be connected with the cathode output end of diode rectifier U after described current sense amplifier IP1 is connected with the in-phase end of current sense amplifier IP2, and the equal ground connection of the end of oppisite phase of current sense amplifier IP1 and current sense amplifier IP2; The output of current sense amplifier IP1 is connected with the in-phase end of voltage detecting amplifier A, and the output of current sense amplifier IP2 is then connected with the end of oppisite phase of voltage detecting amplifier A; The output of this voltage detecting amplifier A is connected with the in-phase end of current sense amplifier IP3, and the output of current sense amplifier IP3 is then held with the R of voltage comparator U1 and is connected.
Described non-linear negative-feedback circuit is by resistance R3, resistance R4, diode D4, diode D5, and transistor bridge circuits composition; The output of described power amplifier P1 is connected with one end of resistance R4 with the output of transformation feedback circuit and resistance R3 respectively, and the other end of resistance R3 is connected with transistor bridge circuits after diode D4, the other end of resistance R4 is connected with transistor bridge circuits after diode D5.
Described transistor bridge circuits is by triode Q2, triode Q3, one end is connected with the collector electrode of triode Q2, the resistance R5 that the other end is connected with the base stage of triode Q3 after resistance R6, one end is connected with the collector electrode of triode Q3, the resistance R8 that the other end is connected with the base stage of triode Q2 after resistance R7, positive pole is connected with the collector electrode of triode Q2, the electric capacity C6 that negative pole is connected with the base stage of triode Q3, negative pole is connected with the collector electrode of triode Q3, the electric capacity C7 that positive pole is connected with the base stage of transistor Q2, and one end is connected with the base stage of transistor Q2, the resistance R9 of the external+6V power supply of the other end is connected with the base stage of one end with transistor Q3, the resistance R10 of the external+6V power supply of the other end forms, the collector electrode of described transistor Q2 is connected with the tie point of diode D4 with resistance R3, its grounded emitter, the collector electrode of described transistor Q3 is connected with the tie point of diode D5 with resistance R4, its grounded emitter, meanwhile, resistance R7 is connected with the output of power amplifier P1 after resistance R3 through diode D4 in turn with the tie point of resistance R8, and resistance R5 is connected with the output of power amplifier P1 after resistance R4 through diode D5 in turn with the tie point of resistance R6.
Described switched filter circuit is by triode Q1, and electric capacity C1, electric capacity C2, resistance R1, resistance R2 and diode D1 form; The base stage of described triode Q1 forms loop with its collector electrode in turn after resistance R2, diode D1 and resistance R1, and electric capacity C1 and resistance R1 is in parallel, and electric capacity C2 and resistance R2 is in parallel; The collector electrode of triode Q1 is connected with the cathode output end of diode rectifier U, its grounded emitter; Resistance R2 is then connected with the in-phase end of power amplifier P1 with the tie point of diode D1, and the primary coil L1 of transformer T is then in parallel with diode D1.
The diode D2 that described power output circuit is connected with the Same Name of Ends of secondary coil L2 by P pole, N pole is connected with the non-same polarity of secondary coil L2 after electric capacity C3, and the inductance L 4 that one end is connected with the N pole of diode D2, the other end is connected with the non-same polarity of secondary coil L2 after electric capacity C4 forms.
Described transformation feedback circuit is made up of diode D3 and electric capacity C5; The P pole of described diode D3 is connected with the non-same polarity of secondary coil L3, its N pole is connected with the Same Name of Ends of secondary coil L3 after electric capacity C5, the Same Name of Ends ground connection of described secondary coil L3; Meanwhile, the output of power amplifier P1 is also connected with the tie point of electric capacity C5 with triode D3.
The utility model comparatively prior art is compared, and has the following advantages and beneficial effect:
(1) the utility model utilizes the nonlinear characteristic of non-linear negative-feedback circuit, adjustable pipe is made automatically to be in edge, saturation region, not only effectively reduce circuit self and external radio frequency interference, but also greatly simplify circuit structure, cost of manufacture and maintenance cost are had reduction by a relatively large margin.
(2) the utility model have employed current sense amplifier circuit to realize current detecting, effectively can improve the loaded current of Switching Power Supply, makes its range of application more extensive.
(3) the utility model can regulate the number of turn of primary transformer coil automatically, therefore, it is possible to carry out pressure regulation according to the actual demand of people.
(4) the utility model effectively can overcome the late effect of Switching Power Supply, can effectively improve Switching Power Supply sensitivity.
Accompanying drawing explanation
Fig. 1 is overall structure schematic diagram of the present utility model.
Embodiment
Below in conjunction with embodiment, the utility model is described in further detail, but execution mode of the present utility model is not limited thereto.
Embodiment
As shown in Figure 1, the constant switching power supply of non-linear negative feedback big current LED described in the utility model includes diode rectifier U, power amplifier P1, transformer T, voltage comparator U1, switched filter circuit, power output circuit, transformation feedback circuit, non-linear negative-feedback circuit, current sense amplifier circuit, ramp generator, slope equalizer M, oscillator and sliding damper.Wherein, transformer T is by the primary coil L1 being arranged on former limit, and the secondary coil L2 and the secondary coil L3 that are arranged on secondary form.The utility model is provided with a sliding tap on the primary coil L1 of transformer T, and this sliding tap is controlled by sliding damper, to guarantee that the utility model can adjust the turn ratio between the primary coil L1 of transformer T and secondary coil L2 and secondary coil L3 automatically.
Wherein, the input of diode rectifier U is used for the civil power of external 220V, between the cathode output end that switched filter circuit is then serially connected in this diode rectifier U and the in-phase end of power amplifier P1.As shown in the figure, this switched filter circuit is by triode Q1, and electric capacity C1, electric capacity C2, resistance R1, resistance R2 and diode D1 form.Wherein, the base stage of triode Q1 forms loop with its collector electrode in turn after resistance R2, diode D1 and resistance R1.Electric capacity C1 and resistance R1 is in parallel, and electric capacity C2 and resistance R2 is in parallel, to form typical RL filter circuit.Meanwhile, the collector electrode of triode Q1 is connected with the cathode output end of diode rectifier U, its grounded emitter.Resistance R2 is then connected with the in-phase end of power amplifier P1 with the tie point of diode D1.Primary coil L1 and the diode D1 of described transformer T are in parallel.
In this switched filter circuit, resistance R1, electric capacity C1 and diode D1 form feedback-clamp circuit, can improve the peak-inverse voltage of conversion efficiency and reduction power amplifier P1 in-phase end.
Current sense amplifier circuit is used for current detecting and the power amplification of diode rectification U, and it is made up of current sense amplifier IP1, current sense amplifier IP2, voltage detecting amplifier A and current sense amplifier IP3.During connection, current sense amplifier IP1 is all connected with the cathode output end of diode rectifier U with the in-phase end of current sense amplifier IP2, and the equal ground connection of the end of oppisite phase of current sense amplifier IP1 and current sense amplifier IP2.
Simultaneously, the output of current sense amplifier IP1 is connected with the in-phase end of voltage detecting amplifier A, the output of current sense amplifier IP2 is then connected with the end of oppisite phase of voltage detecting amplifier A, and the output of voltage detecting amplifier A is then connected with the in-phase end of current sense amplifier IP3.
Voltage comparator U1 comprises three ports, namely R port, Q port and S port is respectively, when connecting, the input of oscillator is held with the S of this voltage comparator U1 and is connected, and its output is then connected with the end of oppisite phase of current sense amplifier IP3 after slope equalizer M through ramp generator in turn.
The output of current sense amplifier IP3 is then held with the R of voltage comparator U1 and is connected, and the Q end of voltage comparator U1 is then connected with the end of oppisite phase of power amplifier P1.
Power output circuit is used for output dc voltage, and it is made up of diode D2, electric capacity C3, inductance L 4 and electric capacity C4.During connection, the P pole of diode D2 is connected with the Same Name of Ends of secondary coil L2, and its N pole is connected with the non-same polarity of secondary coil L2 after electric capacity C3.One end of described inductance L 3 is connected with the N pole of diode D2, the other end is connected with the non-same polarity of secondary coil L2 after electric capacity C4.
Transformation feedback circuit is used for providing feedback voltage for non-linear negative-feedback circuit, and it is made up of diode D3 and electric capacity C5.During connection, the P pole of described diode D3 is connected with the non-same polarity of secondary coil L3, its N pole is connected with the Same Name of Ends of secondary coil L3 after electric capacity C5, the Same Name of Ends ground connection of described secondary coil L3.
Described non-linear negative-feedback circuit is by resistance R3, resistance R4, diode D4, diode D5, and transistor bridge circuits composition.During connection, the output of power amplifier P1 is connected with one end of resistance R4 with the output of transformation feedback circuit and resistance R3 respectively, and the other end of resistance R3 is connected with transistor bridge circuits after diode D4, the other end of resistance R4 is connected with transistor bridge circuits after diode D5.
Described transistor bridge circuits is by triode Q2, and triode Q3, resistance R5, resistance R6, electric capacity C6, resistance R7, resistance R8, electric capacity C7 and resistance R9 and resistance R10 form.During connection, one end of resistance R5 is connected with the collector electrode of triode Q2, and its other end is connected with the base stage of triode Q3 after resistance R6.And one end of resistance R8 is connected with the collector electrode of triode Q3, its other end is connected with the base stage of triode Q2 after resistance R7.
The positive pole of electric capacity C6 is connected with the collector electrode of triode Q2, and its negative pole is connected with the base stage of triode Q3; The negative pole of electric capacity C7 is connected with the collector electrode of triode Q3, and its positive pole is connected with the base stage of transistor Q2.One end of resistance R9 is connected with the base stage of transistor Q2, the external+6V power supply of its other end; One end of resistance R10 is connected with the base stage of transistor Q3, the external+6V power supply of its other end.
Resistance R5 is connected with the tie point of electric capacity C5 with diode D3 through diode D5 with the tie point of resistance R6 after resistance R4; Resistance R7 is then also connected with the tie point of electric capacity C5 with diode D3 after resistance R3 through diode D4 with the tie point of resistance R8.Meanwhile, the collector electrode of described transistor Q2 is connected with the tie point of diode D4 with resistance R3, its grounded emitter; The collector electrode of described transistor Q3 is connected with the tie point of diode D5 with resistance R4, its grounded emitter.
Transistor bridge circuits of the present utility model is symmetrical structure, during use, by turn-on transistor Q2 and transistor Q3, and rely on negative feedback original paper diode D4 and diode D5 automatically to regulate transistor Q2 and transistor Q3 to be in edge, saturation region, thus provide enough driving voltage to regulate the tap of transformer T primary coil L1 for sliding damper, and then change the turn ratio of primary transformer coil L1 and secondary coil L2 and secondary coil L3.
For guaranteeing actual operational effect, the electric capacity C1 in the application, electric capacity C2, electric capacity C3, electric capacity C4, electric capacity C5, electric capacity C6 and electric capacity C7 all adopt patch capacitor to realize.
As mentioned above, just the utility model can well be realized.