CN202679243U - BJT type self-excited Buck converter with small main switch tube driving loss - Google Patents
BJT type self-excited Buck converter with small main switch tube driving loss Download PDFInfo
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- CN202679243U CN202679243U CN 201220228245 CN201220228245U CN202679243U CN 202679243 U CN202679243 U CN 202679243U CN 201220228245 CN201220228245 CN 201220228245 CN 201220228245 U CN201220228245 U CN 201220228245U CN 202679243 U CN202679243 U CN 202679243U
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Abstract
Provided is a BJT type self-excited Buck converter with small main switch tube driving loss, comprising a Buck converter major loop composed of an input capacitor Ci, a main switch tube PNP type BJT tube Q1, a diode D, an inductor L and a capacitor Co and also comprises a main switch tube Q1 driving unit. The main switch tube Q1 driving unit is composed of a resistor R1, a resistor R2, a resistor R3, an NPN type BJT tube Q2 and a PNP type BJT tube Q3. A collector electrode of the NPN type BJT tube Q2 is in connection with one end of the resistor R2, and the other end of the resistor R2 is in connection with a base electrode of the PNP type BJT tube Q1. An emitter electrode of the NPN type BJT tube Q2 is in connection with one end of the resistor R3, and the other end of the resistor R3 is in connection with a negative end of a DC voltage source Vi. A base electrode of the NPN type BJT tube Q2 is in connection with one end of the resistor R1 and an emitter electrode of the PNP type BJT tube Q3; the other end of the resistor R1 is in connection with an emitter electrode of the PNP type BJT tube Q1; a base electrode of the PNP type BJT tube Q3 is in connection with a collector electrode of the PNP type BJT tube Q1; a collector electrode of the PNP type BJT tube Q3 is in connection with the negative end of the DC voltage source Vi.
Description
Technical field
The utility model relates to autonomous DC-DC (DC-DC) converter, is applied to switch voltage-stabilizing or stabilized current power supply, high-brightness LED drive circuit etc., especially a kind of auto-excitation type Buck converter.
Background technology
Compare with separated exciting DC-DC converter with linear (voltage stabilizing or current stabilization) adjuster, auto-excitation type DC-DC converter has the high remarkable advantage of cost performance.What Fig. 1 provided is that a kind of circuit structure is simple, the BJT(bipolar transistor that the components and parts number is few) type auto-excitation type Buck converter, comprise by input capacitance Ci, positive-negative-positive BJT manages Q1, inductance L, the major loop of the Buck converter that diode D and output capacitance Co form, input capacitance Ci is in parallel with direct voltage source Vi, output capacitance Co both end voltage is VD Vo, load Ro is in parallel with output capacitance Co, the negative terminal of direct voltage source Vi links to each other with the negative terminal of VD Vo and the anode of diode D, the anode of direct voltage source Vi links to each other with the emitter of positive-negative-positive BJT pipe Q1, the collector electrode of positive-negative-positive BJT pipe Q1 links to each other with an end of inductance L and the negative electrode of diode D, and the other end of inductance L links to each other with the anode of VD Vo.BJT type auto-excitation type Buck converter shown in Figure 1 also comprises the driver element of main switch Q1, the driver element of described main switch Q1 is by resistance R 1, resistance R 2, resistance R 3, capacitor C 1 and positive-negative-positive BJT pipe Q2 form, the emitter and collector of described positive-negative-positive BJT pipe Q2 links to each other with base stage with the emitter of positive-negative-positive BJT pipe Q1 respectively, the base stage of positive-negative-positive BJT pipe Q1 also is connected to the negative terminal of direct voltage source Vi by resistance R 1, resistance R 3 and capacitor C 1 form parallel branch, one end of described parallel branch links to each other with the collector electrode of positive-negative-positive BJT pipe Q1, the other end of described parallel branch links to each other with the base stage of positive-negative-positive BJT pipe Q2 and an end of resistance R 2, and the other end of resistance R 2 links to each other with the emitter of positive-negative-positive BJT pipe Q2.BJT type auto-excitation type Buck converter shown in Figure 1 also comprises the Voltage Feedback branch road, described Voltage Feedback props up route resistance R 4, resistance R 5, voltage-stabiliser tube Z1 and NPN type BJT pipe Q3 and forms, the negative electrode of described voltage-stabiliser tube Z1 links to each other with the anode of output voltage V o, the anode of voltage-stabiliser tube Z1 links to each other with an end of resistance R 5 and the base stage of NPN type BJT pipe Q3, the emitter of NPN type BJT pipe Q3 links to each other with the other end of resistance R 5 and the negative terminal of direct voltage source Vi, and the collector electrode of NPN type BJT pipe Q3 links to each other by the base stage of resistance R 4 with positive-negative-positive BJT pipe Q2.The weak point of this circuit is: by the driver element that drives the main switch Q1 that resistance R 1, positive-negative-positive BJT pipe Q2, resistance R 2, resistance R 3 and capacitor C 1 form, when main switch Q1 turn-offs, still have larger electric current to flow through and drive resistance R 1, cause the driving loss of Q1 larger, thereby affect the efficient of circuit, especially the light-load efficiency of circuit.
Summary of the invention
Drive the larger deficiency of loss for overcoming existing BJT type auto-excitation type Buck converter main switch, the utility model provides a kind of main switch to drive the little BJT type auto-excitation type Buck converter of loss.
The technical scheme that its technical problem that solves the utility model adopts is: a kind of main switch drives the little BJT type auto-excitation type Buck converter of loss and comprises by input capacitance Ci, positive-negative-positive BJT manages Q1, diode D, the major loop of the Buck converter that inductance L and capacitor C o form, input capacitance Ci is in parallel with direct voltage source Vi, output capacitance Co both end voltage is VD Vo, load Ro is in parallel with output capacitance Co, the negative terminal of direct voltage source Vi links to each other with the negative terminal of VD Vo and the anode of diode D, the anode of direct voltage source Vi links to each other with the emitter of positive-negative-positive BJT pipe Q1, the collector electrode of positive-negative-positive BJT pipe Q1 links to each other with an end of inductance L and the negative electrode of diode D, and the other end of inductance L links to each other with the anode of VD Vo.Described main switch drives the driver element that the little BJT type auto-excitation type Buck converter of loss also comprises main switch Q1, the driver element of described main switch Q1 is by resistance R 1, resistance R 2, resistance R 3, NPN type BJT pipe Q2 and positive-negative-positive BJT pipe Q3 form, the collector electrode of described NPN type BJT pipe Q2 links to each other with an end of resistance R 2, the other end of resistance R 2 links to each other with the base stage of positive-negative-positive BJT pipe Q1, the emitter of NPN type BJT pipe Q2 links to each other with an end of resistance R 3, the other end of resistance R 3 links to each other with the negative terminal of direct voltage source Vi, the base stage of NPN type BJT pipe Q2 links to each other with the emitter of an end of resistance R 1 and positive-negative-positive BJT pipe Q3, the other end of resistance R 1 links to each other with the emitter of positive-negative-positive BJT pipe Q1, the base stage of positive-negative-positive BJT pipe Q3 links to each other with the collector electrode of positive-negative-positive BJT pipe Q1, and the collector electrode of positive-negative-positive BJT pipe Q3 links to each other with the negative terminal of direct voltage source Vi.Be the dynamic property of raising circuit, but emitter and the base stage two ends shunt capacitance C1 of described positive-negative-positive BJT pipe Q3.In addition, but positive-negative-positive BJT manages the collector electrode reconfiguration of Q3 in the collector electrode of positive-negative-positive BJT pipe Q1, but 3 short circuits of described resistance R.
Further, as preferred a kind of scheme: described main switch drives the little BJT type auto-excitation type Buck converter of loss and also comprises the Voltage Feedback branch road, described Voltage Feedback props up route resistance R 4, resistance R 5, voltage-stabiliser tube Z1 and NPN type BJT pipe Q4 form, the collector electrode of described NPN type BJT pipe Q4 links to each other with an end of resistance R 4, the other end of resistance R 4 links to each other with the base stage of NPN type BJT pipe Q2, the emitter of NPN type BJT pipe Q4 links to each other with the negative terminal of direct voltage source Vi and an end of resistance R 5, the base stage of NPN type BJT pipe Q4 links to each other with the other end of resistance R 5 and the anode of voltage-stabiliser tube Z1, and the negative electrode of voltage-stabiliser tube Z1 links to each other with the anode of output voltage V o.Be the dynamic property of raising circuit, but the two ends shunt capacitance C2 of described voltage-stabiliser tube Z1.
Perhaps, as preferred another kind of scheme: described main switch drives the little BJT type auto-excitation type Buck converter of loss and also comprises the current feedback branch road, described current feedback is propped up route resistance R 4, resistance R 5, resistance R 6, diode D1 and NPN type BJT pipe Q4 form, the collector electrode of described NPN type BJT pipe Q4 links to each other with an end of resistance R 4, the other end of resistance R 4 links to each other with the base stage of NPN type BJT pipe Q2, the emitter of NPN type BJT pipe Q4 links to each other with the negative terminal of direct voltage source Vi, the base stage of NPN type BJT pipe Q4 links to each other with an end of resistance R 5 and the anode of diode D1, the other end of resistance R 5 links to each other with the anode of direct voltage source Vi, the negative terminal of the negative electrode of diode D1 and output voltage V o, the end of capacitor C o and an end of resistance R 6 link to each other, and the other end of resistance R 6 links to each other with the negative terminal of direct voltage source Vi and the anode of diode D.Be the dynamic property of raising circuit, but the two ends shunt capacitance C2 of described resistance R 5.Further, position and the connected mode capable of regulating of described resistance R 6 and diode D1 are as follows: an end of resistance R 6 links to each other with the negative electrode of the negative terminal of output voltage V o and diode D1, the other end of resistance R 6 links to each other with the end of capacitor C o, the anode of diode D and the negative terminal of direct voltage source Vi, and the anode of diode D1 still links to each other with the base stage of NPN type BJT pipe Q4.
Technical conceive of the present utility model is: on the basis of existing BJT type auto-excitation type Buck converter shown in Figure 1, replace former lossy large main switch driver element (shown in Fig. 2 ~ 5) with the little main switch driver element of loss.The little main switch driver element of loss is comprised of resistance R 1, resistance R 2, resistance R 3, NPN type BJT pipe Q2 and positive-negative-positive BJT pipe Q3.Its feature is as follows: an end of resistance R 1 links to each other with the emitter of main switch positive-negative-positive BJT pipe Q1 and the anode of direct voltage source Vi, the other end of described resistance R 1 links to each other with the base stage of NPN type BJT pipe Q2 and the emitter of positive-negative-positive BJT pipe Q3, the collector electrode of described NPN type BJT pipe Q2 links to each other with an end of resistance R 2, the other end of described resistance R 2 links to each other with the base stage of main switch Q1, the emitter of described NPN type BJT pipe Q2 links to each other with an end of resistance R 3, the other end of described resistance R 3 links to each other with the collector electrode of positive-negative-positive BJT pipe Q3 and the negative terminal of direct voltage source Vi, and the base stage of described positive-negative-positive BJT pipe Q3 links to each other with the collector electrode of main switch Q1.For improving the dynamic property of whole circuit, can be at emitter and the base stage two ends shunt capacitance C1 of positive-negative-positive BJT pipe Q3.In addition, but positive-negative-positive BJT manages the collector electrode reconfiguration of Q3 in the collector electrode of positive-negative-positive BJT pipe Q1, but resistance R 3 short circuits.
For obtaining stable VD, between the output of Buck converter major loop and main switch driver element, can increase a Voltage Feedback branch road, form (such as Fig. 2 and shown in Figure 4) by NPN type BJT pipe Q4, resistance R 4, resistance R 5, voltage-stabiliser tube Z1.For improving the dynamic property of whole circuit, can be at voltage-stabiliser tube Z1 two ends shunt capacitance C2.
For obtaining stable average anode current, between the output of Buck converter major loop and main switch driver element, can increase a current feedback branch road, form (such as Fig. 3 and shown in Figure 5) by NPN type BJT pipe Q4, resistance R 4, resistance R 5, resistance R 6, diode D1.For improving the dynamic property of whole circuit, can be at resistance R 5 two ends shunt capacitance C2.
The beneficial effects of the utility model are mainly manifested in: the BJT type auto-excitation type Buck converter that the utility model proposes not only has the advantage that circuit structure is simple, the components and parts number is few, drive the advantage that loss is little, light-load efficiency is high but also have main switch, be fit to very much switch voltage-stabilizing or the application such as stabilized current power supply, high-brightness LED drive circuit of small-power (several watts of levels are following) voltage-dropping type.
Description of drawings
Fig. 1 is the circuit diagram of existing a kind of BJT type auto-excitation type Buck converter.
Fig. 2 is the circuit diagram that main switch drives the little BJT type auto-excitation type Buck converter embodiment 1 of loss.
Fig. 3 is the circuit diagram that main switch drives the little BJT type auto-excitation type Buck converter embodiment 2 of loss.
Fig. 4 is the circuit diagram that main switch drives the little BJT type auto-excitation type Buck converter embodiment 3 of loss.
Fig. 5 is the circuit diagram that main switch drives the little BJT type auto-excitation type Buck converter embodiment 4 of loss.
Fig. 6 is that main switch drives little BJT type auto-excitation type Buck converter embodiment 1 and the ideal waveform figure of embodiment 3 under inductive current iL critical continuous mode mode of operation of loss.
Fig. 7 is that main switch drives the little ideal waveform figure of BJT type auto-excitation type Buck converter embodiment 2 under inductive current iL critical continuous mode mode of operation of loss.
Fig. 8 is that main switch drives the little ideal waveform figure of BJT type auto-excitation type Buck converter embodiment 4 under inductive current iL critical continuous mode mode of operation of loss.
Embodiment
Below in conjunction with accompanying drawing the utility model is further described.
Embodiment 1
With reference to Fig. 2 and Fig. 6, a kind of main switch drives the little BJT type auto-excitation type Buck converter of loss and comprises by input capacitance Ci, positive-negative-positive BJT manages Q1, diode D, the major loop of the Buck converter that inductance L and capacitor C o form, input capacitance Ci is in parallel with direct voltage source Vi, output capacitance Co both end voltage is VD Vo, load Ro is in parallel with output capacitance Co, the negative terminal of direct voltage source Vi links to each other with the negative terminal of VD Vo and the anode of diode D, the anode of direct voltage source Vi links to each other with the emitter of positive-negative-positive BJT pipe Q1, the collector electrode of positive-negative-positive BJT pipe Q1 links to each other with an end of inductance L and the negative electrode of diode D, and the other end of inductance L links to each other with the anode of VD Vo.Described main switch drives the driver element that the little BJT type auto-excitation type Buck converter of loss also comprises main switch Q1, the driver element of described main switch Q1 is by resistance R 1, resistance R 2, resistance R 3, capacitor C 1, NPN type BJT pipe Q2 and positive-negative-positive BJT pipe Q3 form, the collector electrode of described NPN type BJT pipe Q2 links to each other with an end of resistance R 2, the other end of resistance R 2 links to each other with the base stage of positive-negative-positive BJT pipe Q1, the emitter of NPN type BJT pipe Q2 links to each other with an end of resistance R 3, the other end of resistance R 3 links to each other with the negative terminal of direct voltage source Vi, the base stage of NPN type BJT pipe Q2 links to each other with the emitter of an end of resistance R 1 and positive-negative-positive BJT pipe Q3, the other end of resistance R 1 links to each other with the emitter of positive-negative-positive BJT pipe Q1, the base stage of positive-negative-positive BJT pipe Q3 links to each other with the collector electrode of positive-negative-positive BJT pipe Q1, and the collector electrode of positive-negative-positive BJTQ3 links to each other with the negative terminal of direct voltage source Vi.For improving the dynamic property of circuit, emitter and the base stage two ends shunt capacitance C1 of described positive-negative-positive BJT pipe Q3.
Fig. 2 is the circuit diagram that main switch drives the little BJT type auto-excitation type Buck converter embodiment 1 of loss, has adopted the Voltage Feedback branch road.Described Voltage Feedback branch road comprises NPN type BJT pipe Q4, resistance R 4, resistance R 5, voltage-stabiliser tube Z1 and capacitor C 2, the collector electrode of NPN type BJT pipe Q4 links to each other with an end of resistance R 4, the other end of resistance R 4 links to each other with the base stage of NPN type BJT pipe Q2, the emitter of NPN type BJT pipe Q4 links to each other with the negative terminal of direct voltage source Vi and an end of resistance R 5, the base stage of NPN type BJT pipe Q4 links to each other with the other end of resistance R 5 and the anode of voltage-stabiliser tube Z1, and the negative electrode of voltage-stabiliser tube Z1 links to each other with the anode of output voltage V o.For improving the dynamic property of circuit, the two ends shunt capacitance C2 of described voltage-stabiliser tube Z1.
Fig. 6 is that main switch drives the little ideal waveform figure of BJT type auto-excitation type Buck converter embodiment 1 under inductive current iL critical continuous mode mode of operation of loss.Its circuit working principle is specific as follows: in (1) circuit electrifying startup stage: t=t0 moment, circuit powers on, direct voltage source Vi(vi) rise since 0.Just begin, Q1, Q2, Q3, Q4 and D all end, output voltage V o(vo) be 0.The t=t1 moment, when namely vi rises to certain value, Q2 conducting, and then Q1 conducting.After the Q1 conducting, vi, Q1, L, Co and Ro form the loop, the inductance L charging, and inductive current iL and output voltage vo increase.Along with the increase of iL, Q1 collector current ic1 and emitter-collector voltage vec1 also increases thereupon, causes the collector voltage vc1 of Q1 to fall.The t=t2 moment, when namely vc1 drops into certain value, the Q3 conducting, Q2 turn-offs, and then Q1 turn-offs.Q1 closes and has no progeny, the D conducting, and D, L, Co and Ro form the loop, the inductance L discharge, inductive current iL reduces.In the t=t3 moment, inductive current iL is reduced to 0, D cut-off.After the D cut-off, the Q2 conducting, Q3 turn-offs, and then again conducting of Q1, and circuit enters the next self-excitation work period.Go through several cycles, after the output voltage of circuit reached set point Vo, circuit had just been finished the electrifying startup process, entered the steady operation stage.(2) the circuit steady operation stage: after the output voltage of circuit reached set point Vo, the Voltage Feedback branch road of circuit just began to work.When output voltage was higher than set point Vo, the effect by Z1 made the Q4 conducting, and then Q2 and Q1 turn-off, and by the ON time (being t5-t4) that shortens Q1, the deadline (being t6-t5) that prolongs Q1, realized the reduction of output voltage.When output voltage was lower than set point Vo, Z1 was inoperative, and Q4 turn-offs, and recovers again the conducting of Q1 and deadline former state, realized the lifting of output voltage.Thus, circuit can realize exporting voltage stabilizing.
With reference to Fig. 3 and Fig. 7, present embodiment comprises the major loop of the Buck converter that is comprised of input capacitance Ci, positive-negative-positive BJT pipe Q1, diode D, inductance L and capacitor C o and the driver element of managing the main switch Q1 that Q3 forms by resistance R 1, resistance R 2, resistance R 3, capacitor C 1, NPN type BJT pipe Q2 and positive-negative-positive BJT, also comprises the current feedback branch road.Described current feedback branch road comprises detection resistance R 6, NPN type BJT manages Q4, resistance R 4, resistance R 5, capacitor C 2 and diode D1, the collector electrode of NPN type BJT pipe Q4 links to each other with an end of resistance R 4, the other end of resistance R 4 links to each other with the base stage of NPN type BJT pipe Q2, the emitter of NPN type BJT pipe Q4 links to each other with the negative terminal of direct voltage source Vi, the base stage of NPN type BJT pipe Q4 links to each other with an end of resistance R 5 and the anode of diode D1, the other end of resistance R 5 links to each other with the anode of direct voltage source Vi, the negative terminal of the negative electrode of diode D1 and output voltage V o, the end of capacitor C o and an end of resistance R 6 link to each other, and the other end of resistance R 6 links to each other with the negative terminal of direct voltage source Vi and the anode of diode D.For improving the dynamic property of circuit, described resistance R 5 two ends shunt capacitance C2.
Other circuit structures of present embodiment are identical with embodiment 1.
Fig. 7 is that main switch drives the little ideal waveform figure of BJT type auto-excitation type Buck converter embodiment 2 under inductive current iL critical continuous mode mode of operation of loss.Its circuit working principle is specific as follows:
(1) the circuit electrifying startup stage: similar to embodiment 1, go through several cycles, after the inductive current iL of circuit reached set point ILmax, circuit had just been finished the electrifying startup process, entered the steady operation stage.
(2) the circuit steady operation stage: after the inductive current iL of circuit reached set point ILmax, the current feedback branch road of circuit just began to work.As the inductive current iL of circuit during greater than set point ILmax, D1 and R6 work and make the Q4 conducting, and then Q2 and Q1 turn-off, and inductive current iL are reduced until be 0.Subsequently, circuit enters the next steady operation cycle.Because of circuit working under inductive current iL critical continuous mode mode of operation, output current Io=ILmax/2.Thus, circuit can realize exporting current stabilization.
Embodiment 3
With reference to Fig. 4 and Fig. 6, present embodiment comprises the major loop of the Buck converter that is comprised of input capacitance Ci, positive-negative-positive BJT pipe Q1, diode D, inductance L and capacitor C o, also comprises the driver element of main switch Q1.The driver element of described main switch Q1 is by resistance R 1, resistance R 2, resistance R 3, capacitor C 1, NPN type BJT pipe Q2 and positive-negative-positive BJT pipe Q3 form, the collector electrode of described NPN type BJT pipe Q2 links to each other with an end of resistance R 2, the other end of resistance R 2 links to each other with the base stage of positive-negative-positive BJT pipe Q1, the emitter of NPN type BJT pipe Q2 links to each other with an end of resistance R 3, the other end of resistance R 3 links to each other with the negative terminal of direct voltage source Vi, the base stage of NPN type BJT pipe Q2 links to each other with the emitter of an end of resistance R 1 and positive-negative-positive BJT pipe Q3, the other end of resistance R 1 links to each other with the emitter of positive-negative-positive BJT pipe Q1, and the base stage of positive-negative-positive BJT pipe Q3 all links to each other with the collector electrode of positive-negative-positive BJT pipe Q1 with collector electrode.For improving the dynamic property of circuit, emitter and the base stage two ends shunt capacitance C1 of described positive-negative-positive BJT pipe Q3.
Other circuit structures of present embodiment are identical with embodiment 1.
Fig. 6 is that main switch drives the little ideal waveform figure of BJT type auto-excitation type Buck converter embodiment 3 under inductive current iL critical continuous mode mode of operation of loss.Its circuit working principle is similar to embodiment 1, and circuit also can realize exporting voltage stabilizing.
Embodiment 4
With reference to Fig. 5 and Fig. 8, present embodiment comprises the major loop of the Buck converter that is comprised of input capacitance Ci, positive-negative-positive BJT pipe Q1, diode D, inductance L and capacitor C o, also comprises the driver element of main switch Q1.The driver element of described main switch Q1 is by resistance R 1, resistance R 2, capacitor C 1, NPN type BJT pipe Q2 and positive-negative-positive BJT pipe Q3 form, the collector electrode of described NPN type BJT pipe Q2 links to each other with an end of resistance R 2, the other end of resistance R 2 links to each other with the base stage of positive-negative-positive BJT pipe Q1, the emitter of NPN type BJT pipe Q2 links to each other with the negative terminal of direct voltage source Vi, the base stage of NPN type BJT pipe Q2 links to each other with the emitter of an end of resistance R 1 and positive-negative-positive BJT pipe Q3, the other end of resistance R 1 links to each other with the emitter of positive-negative-positive BJT pipe Q1, the base stage of positive-negative-positive BJT pipe Q3 links to each other with the collector electrode of positive-negative-positive BJT pipe Q1, and the collector electrode of positive-negative-positive BJT Q3 links to each other with the negative terminal of direct voltage source Vi.For improving the dynamic property of circuit, emitter and the base stage two ends shunt capacitance C1 of described positive-negative-positive BJT pipe Q3.
Present embodiment also comprises the current feedback branch road, described current feedback branch road comprises detection resistance R 6, NPN type BJT manages Q4, resistance R 4, resistance R 5, capacitor C 2 and diode D1, the collector electrode of NPN type BJT Q4 links to each other with an end of resistance R 4, the other end of resistance R 4 links to each other with the base stage of NPN type BJT pipe Q2, the emitter of NPN type BJT pipe Q4 links to each other with the negative terminal of direct voltage source Vi, the base stage of NPN type BJT pipe Q4 links to each other with an end of resistance R 5 and the anode of diode D1, the other end of resistance R 5 links to each other with the anode of direct voltage source Vi, the negative electrode of diode D1 links to each other the end of the other end of resistance R 6 and capacitor C o with the negative terminal of output voltage V o and an end of resistance R 6, the negative terminal of the anode of diode D and direct voltage source Vi links to each other.For improving the dynamic property of circuit, described resistance R 5 two ends shunt capacitance C2.
Other circuit structures of present embodiment are identical with embodiment 1.
Fig. 8 is that main switch drives the little ideal waveform figure of BJT type auto-excitation type Buck converter embodiment 4 under inductive current iL critical continuous mode mode of operation of loss.Its circuit working principle is specific as follows:
(1) the circuit electrifying startup stage: similar to embodiment 1, go through several cycles, after the output current of circuit reached set point Io, circuit had just been finished the electrifying startup process, entered the steady operation stage.
(2) the circuit steady operation stage: after the output current of circuit reached set point Io, the current feedback branch road of circuit just began to work.When output current during greater than set point Io, the effect by D1 and R6 makes the Q4 conducting, and then Q2 and Q1 turn-off, and by the ON time (being t5-t4) that shortens Q1, the deadline (being t6-t5) that prolongs Q1, realizes reducing of output current.When output current during less than set point Io, D1 and R6 are inoperative, and Q4 turn-offs, and recovers again the conducting of Q1 and deadline former state, realizes the lifting of output current.Thus, circuit can realize exporting current stabilization.
The described content of this specification embodiment only is enumerating the way of realization of utility model design; protection range of the present utility model should not be regarded as only limiting to the concrete form that embodiment states, protection range of the present utility model also reaches the equivalent technologies means that design can be expected according to the utility model in those skilled in the art.
Claims (9)
1. the little BJT type auto-excitation type Buck converter of main switch driving loss comprises by input capacitance Ci, positive-negative-positive BJT manages Q1, diode D, the major loop of the Buck converter that inductance L and capacitor C o form, input capacitance Ci is in parallel with direct voltage source Vi, output capacitance Co both end voltage is VD Vo, load Ro is in parallel with output capacitance Co, the negative terminal of direct voltage source Vi links to each other with the negative terminal of VD Vo and the anode of diode D, the anode of direct voltage source Vi links to each other with the emitter of positive-negative-positive BJT pipe Q1, the collector electrode of positive-negative-positive BJT pipe Q1 links to each other with an end of inductance L and the negative electrode of diode D, the other end of inductance L links to each other with the anode of VD Vo, it is characterized in that: described auto-excitation type Buck converter also comprises the driver element of main switch Q1, the driver element of described main switch Q1 is by resistance R 1, resistance R 2, resistance R 3, NPN type BJT pipe Q2 and positive-negative-positive BJT pipe Q3 form, the collector electrode of described NPN type BJT pipe Q2 links to each other with an end of resistance R 2, the other end of resistance R 2 links to each other with the base stage of positive-negative-positive BJT pipe Q1, the emitter of NPN type BJT pipe Q2 links to each other with an end of resistance R 3, the other end of resistance R 3 links to each other with the negative terminal of direct voltage source Vi, the base stage of NPN type BJT pipe Q2 links to each other with the emitter of an end of resistance R 1 and positive-negative-positive BJT pipe Q3, the other end of resistance R 1 links to each other with the emitter of positive-negative-positive BJT pipe Q1, the base stage of positive-negative-positive BJT pipe Q3 links to each other with the collector electrode of positive-negative-positive BJT pipe Q1, and the collector electrode of positive-negative-positive BJT pipe Q3 links to each other with the negative terminal of direct voltage source Vi.
2. main switch as claimed in claim 1 drives the little BJT type auto-excitation type Buck converter of loss, it is characterized in that: the collector electrode reconfiguration of described positive-negative-positive BJT pipe Q3 is in the collector electrode of positive-negative-positive BJT pipe Q1.
3. main switch as claimed in claim 1 drives the little BJT type auto-excitation type Buck converter of loss, it is characterized in that: emitter and the base stage two ends shunt capacitance C1 of described positive-negative-positive BJT pipe Q3.
4. main switch as claimed in claim 2 drives the little BJT type auto-excitation type Buck converter of loss, it is characterized in that: emitter and the base stage two ends shunt capacitance C1 of described positive-negative-positive BJT pipe Q3.
5. drive the little BJT type auto-excitation type Buck converter of loss such as the described main switch of one of claim 1～4, it is characterized in that: described auto-excitation type Buck converter also comprises the Voltage Feedback branch road, described Voltage Feedback props up route resistance R 4, resistance R 5, voltage-stabiliser tube Z1 and NPN type BJT pipe Q4 form, the collector electrode of described NPN type BJT pipe Q4 links to each other with an end of resistance R 4, the other end of resistance R 4 links to each other with the base stage of NPN type BJT pipe Q2, the emitter of NPN type BJT pipe Q4 links to each other with the negative terminal of direct voltage source Vi and an end of resistance R 5, the base stage of NPN type BJT pipe Q4 links to each other with the other end of resistance R 5 and the anode of voltage-stabiliser tube Z1, and the negative electrode of voltage-stabiliser tube Z1 links to each other with the anode of output voltage V o.
6. main switch as claimed in claim 5 drives the little BJT type auto-excitation type Buck converter of loss, it is characterized in that: the two ends shunt capacitance C2 of described voltage-stabiliser tube Z1.
7. drive the little BJT type auto-excitation type Buck converter of loss such as the described main switch of one of claim 1～4, it is characterized in that: described auto-excitation type Buck converter also comprises the current feedback branch road, described current feedback is propped up route resistance R 4, resistance R 5, resistance R 6, diode D1 and NPN type BJT pipe Q4 form, the collector electrode of described NPN type BJT pipe Q4 links to each other with an end of resistance R 4, the other end of resistance R 4 links to each other with the base stage of NPN type BJT pipe Q2, the emitter of NPN type BJT pipe Q4 links to each other with the negative terminal of direct voltage source Vi, the base stage of NPN type BJT pipe Q4 links to each other with an end of resistance R 5 and the anode of diode D1, the other end of resistance R 5 links to each other with the anode of direct voltage source Vi, the negative terminal of the negative electrode of diode D1 and output voltage V o, the end of capacitor C o and an end of resistance R 6 link to each other, and the other end of resistance R 6 links to each other with the negative terminal of direct voltage source Vi and the anode of diode D.
8. drive the little BJT type auto-excitation type Buck converter of loss such as the described main switch of one of claim 1～4, it is characterized in that: described auto-excitation type Buck converter also comprises the current feedback branch road, described current feedback is propped up route resistance R 4, resistance R 5, resistance R 6, diode D1 and NPN type BJT pipe Q4 form, the collector electrode of described NPN type BJT pipe Q4 links to each other with an end of resistance R 4, the other end of resistance R 4 links to each other with the base stage of NPN type BJT pipe Q2, the emitter of NPN type BJT pipe Q4 links to each other with the negative terminal of direct voltage source Vi, the base stage of NPN type BJT pipe Q4 links to each other with an end of resistance R 5 and the anode of diode D1, the other end of resistance R 5 links to each other with the anode of direct voltage source Vi, the negative electrode of diode D1 links to each other the end of the other end of resistance R 6 and capacitor C o with the negative terminal of output voltage V o and an end of resistance R 6, the negative terminal of the anode of diode D and direct voltage source Vi links to each other.
9. main switch as claimed in claim 8 drives the little BJT type auto-excitation type Buck converter of loss, it is characterized in that: the two ends shunt capacitance C2 of described resistance R 5.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220228245 CN202679243U (en) | 2012-05-17 | 2012-05-17 | BJT type self-excited Buck converter with small main switch tube driving loss |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220228245 CN202679243U (en) | 2012-05-17 | 2012-05-17 | BJT type self-excited Buck converter with small main switch tube driving loss |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102820784A (en) * | 2012-05-17 | 2012-12-12 | 浙江工业大学 | BJT (bipolar junction transistor)-type auto-excitation Buck converter with small main switching tube driving loss |
| CN110572014A (en) * | 2019-08-29 | 2019-12-13 | 合肥博雷电气有限公司 | MOS tube driving circuit with turn-off negative voltage |
-
2012
- 2012-05-17 CN CN 201220228245 patent/CN202679243U/en not_active Expired - Lifetime
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102820784A (en) * | 2012-05-17 | 2012-12-12 | 浙江工业大学 | BJT (bipolar junction transistor)-type auto-excitation Buck converter with small main switching tube driving loss |
| CN102820784B (en) * | 2012-05-17 | 2014-11-12 | 浙江工业大学 | BJT (bipolar junction transistor)-type auto-excitation Buck converter with small main switching tube driving loss |
| CN110572014A (en) * | 2019-08-29 | 2019-12-13 | 合肥博雷电气有限公司 | MOS tube driving circuit with turn-off negative voltage |
| CN110572014B (en) * | 2019-08-29 | 2021-03-30 | 合肥博雷电气有限公司 | MOS tube driving circuit with turn-off negative voltage |
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