TWI278171B - Light loading control circuit for a buck-boost voltage converter - Google Patents

Abstract

A light loading control circuit operates a switching circuit of a buck-boost voltage converter alternately in a plurality of phase cycles and a sleep period. Each phase cycle has a rising phase, a falling phase, and a maintaining phase. In the rising phase, the switching circuit is operated to increase an inductor current. In the falling phase, the switching circuit is operated to decrease the inductor current. In the maintaining phase, the switching circuit is operated to keep the inductor current approximately constant. The sleep period prevents two terminals of an inductor from being respectively coupled to two selected from a group consisting of an input voltage, an output voltage, and a ground potential.

Description

1278171 IX. Description of the invention: 〃 [Technical field to which the invention pertains] In particular, the present invention relates to a light load control circuit for a DC/DC electric reed I flat-panel type 33⁄4 type of step-up voltage converter. [°] [Prior Art] FIG. 1 shows a conventional lift-down voltage converter. The conventional step-up voltage converter includes a circuit diagram. Referring to the drawing, a lift control circuit, a drive circuit 12, a switch circuit 1, and a circuit 13. And a light load control lift control circuit 11 based on the output voltage voltage-voltage conversion control (four) vcs feedback, and the production drive power ... generate four drive 'should: voltage conversion control signal drive switch unit... two move = Guided month / seven τ, first, the hunter is suitable to control the switching unit S1 to,,, 5 V-pass, and the on-time or non-conduction of the case of fl +, the input of the electricity can be effectively compared to the snow Mao Wuzhen output voltage vout, and in the electric house Vin can be greater than, and so on. ..., the middle of the transfer knowing the skill has been in the flat ancient eve of the voltage vout. There are many types of national patents on the π, 166, 527 盥 盥 Η 'Control circuit 1 such as the circuit and method of the United States. '88, 〇33 and other technical literature revealed: load current 昼 conversion efficiency required for load 50, the conventional rise J $ "in the operation of electricity. In the light load mode load mode, only the mouth should be lifted Control Lei Dan, and quite the voltage conversion control signal VCS, I278l7l If the load current exceeds the equation _ wheel current I. One by one, then the weight of the lift: the maximum light negative wear average light negative wear mode, making its operation re Back: The voltage converter will leave the system. The control of the mouth-to-lift control circuit is as described above, regardless of the wheel voltage V-, the lift type ln ', y, equal, or less than _ ^ I The converter can convert the input voltage to a predetermined output voltage and convert to a wide range H a _ ', that is, the 'lifting money converter can have a wide-ranging round-in voltage γ. The change will affect the light load mode ^ π ln,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, Carrying out his "V number will consider the equation (1) for the input Ray 厌 v partial Operation 'can be obtained the following equation ⑺ ·· m 0 --- / QV. J OMi_ave (max)

(2) Since the square type (2) is a function of 轮. Λ ^ ln, the input voltage Vin is recognized, and the face U is caused to rise and fall for different in-load and load control circuits 13 Different maximum light loads are flatter in the private mode of the house. ,: Rain current [ 〖, coffee called to leave light and negative, however, what we expect is a light load yoke in a wide range of wheeled power (four) load control system, can be - wheel load mode start and termination. Drop-type electric castle conversion [invention content] There is a turtle in the above-mentioned question light weight, one of the purposes of this one is to provide ~ 1278171 Fort conversion efficiency, depending on the power of the lift, the pressure converter will enter: The light load is no longer followed. In the operation of the load-carrying type, the drive circuit 32 is no longer in response to the voltage conversion control generated by the lift control circuit 31, which is generated by the lift control circuit 31. The light load control circuit "controlled segment =., the load control circuit 33 includes - the start unit μ, the first order I::; a sleep control unit 37, and - the stop unit %. Start early 7G 3 5 system for detecting Leiwei cold I supplies a π~, then 冤 电 / melon 1L and the inductor current L 氐 一 一 一 临界 LM LM LM LM π th 守 触 触 产生 产生 产生 产生Help L is LM. In response to the light gp gr A; i., 戟 start L 唬 LM, the drive circuit 32 is controlled by the Belle control circuit 33 to control the efficiency of the light load mode. For example, s, the startup single-current comparator is implemented as early as 70 35 by T /:b, θ ^ is used to compare the inductor current The critical electrical &

Jth, so that when the electric salt mine, the six τ 7 , such as the Qiao 丨 motor electric level 窀 machine IL is triggered below the critical current is triggered _ g Gong private I motor 扎 tt staff load start signal LM. The phase control unit K i 6 is used to make the synchronous switching circuit cycle in a phase, and is prepared in the middle. The mother phase has a rising phase, a falling phase, and a one-dimensional Ktb hunger. Keep it ^ 1 again. As shown in FIG. 4, in the rising order ρ φ , that is, from time t1 to t2, the snow is in the middle, and the I1 is in the middle, and the inductance k II rises from a predetermined valley value Ih to a predetermined The peak value τ ^ value Ibm is linear to...inductive electricity production Pk. In the falling phase, that is, from time t2 "7, the L U undershoot I k linearly falls to the valley phase, that is, from the time n n s ▼. The value is Ibm. In the maintenance of f between t3 and t4, the state of the inductor current J is fixed, that is, it is difficult to 拄 ^ l * is in the solid state, and is allowed to hold the valley value Ibm at time t3. Stage control unit 亓 κ _ ^ ^ ^ 36 fork A current comparator 36-1 is provided, and & + is used to compare the inductor current IL with a cat λα 々 for /, 疋, peak current 1Pk. When the inductor current IL line 12 1278171 current Icut — aveCmax} still cannot meet the actual When the load is applied, the voltage feedback signal Vfb is gradually decreased. Therefore, a threshold voltage vth can be appropriately set so that when the voltage feedback signal Vfb falls below the threshold voltage Vth, the voltage comparator of the termination unit 38 is terminated. A light load termination signal is generated by the trigger. Tiger LX. It should be noted that this critical voltage M Vth must be smaller than the difference between the sleep reference voltage vslp minus the hysteresis voltage Vhys.

In the phase cycle consisting of the rising phase, the falling phase, and the sustaining phase according to the present invention, assuming that the valley current Ibm is set to zero, the maximum light load average output current a that can be supplied can be obtained by the following equation ( 3) Calculated:

I out _ave(max) (I \ lpk κ 12 J fi+d] ’Μ > (3) >7 ^ \ j Turn-out voltage, the boost voltage converter can input the input voltage ν

Switch to a predetermined output voltage v〇ut. That is, the lift type lightning n and the electric argon converter are applied to a wide range of input voltages vin. However, recognize and invade the voltage. Specifically, considering equation (3) for private, bin y, and all-input voltage partial differential operation, the following equation (4) can be obtained: 〇ut-^ave (change in max affects light load mode Maximum light load flat τ, Ding 岣 wheel power out 16 (4) 1278171

a Y _ave(max) dv' Γ ί Μχ equation (2) and equation (4), in the load mode, JL; soil A, according to the light of the present invention

Taking the average light output current rate of the light and light load is decreased due to the change of the surname D 日 t Ut~ave(max). The maintenance phase of the under-reduction is performed in accordance with the present invention to achieve the effect of enhancing the stability of the maximum light load k^ebax. For the power of enmity, the ancient, shovel gentleman, for seeing the input voltage v. According to the light load path of the first embodiment of the present invention, the lifting voltage conversion Μ 33 is stable; the light load type of the genre is activated. Please note that in the present invention, only 砗/, ,, ,stop. It can be implemented by ..., ^ not limited to a fixed value but also by a controllable change value. ^ ^ T ^ ^ 攸 It is rare that the Tm system is proportional to the input voltage Vin, ie:

Tm=k.Vin (5) ^Vapor^proportional number of cranes' The maximum light load average transmission 〇ut-ave(max) according to the present invention can be calculated by the following equation (6): out _ave{msx)

V2y κ J (6) electricity... line micro (four) 17 1278171 ί, :i_〇ve(max) fr)

Kut "vourk J ,l \\xpk

KuTjk U

+F (7) It can be known from equation (7) that the #input voltage ^ satisfies the following equation (8)

K

L k (8) ^ Large load average output current w_ave(max) will not be affected by two =. Therefore, properly select the proportional constant heart: efficiency reduction intrusion: the middle point of the operating range of the plant input voltage Vin, there may be > and beer low input voltage from the parent of n J vln for the maximum light load average output current ° Effect of ut-aVe(max}. 36-3 = The maintenance time control unit according to the first embodiment of the present invention includes reference to Fig. 6, and the maintenance time control unit (6)

Voltage comparator ~-current source im, -capacitance c Μλ electro-crystal 俨ς electric valley Cm, one NM0S body Sm, and a buffer inverter BmQNM〇s transistor 5 as the trigger terminal A of the sustain time control unit 36_3 :: 冲和知w is used to receive the falling end signal ρχ via the slow Bm. The money is compared with the output terminal as the maintenance time control unit 36_3, and the output terminal MX is used to raise and maintain the termination signal MX. At the end of the falling phase, u drops to the valley value..., the falling termination letter; x: that is, the inductor current becomes high 彳ϋ π , b Χ攸 low level quasi-rotation state. Therefore, 匪0S transistor ^ conduction state changes to no Guide 18 1278171 $-like '%' causes the power transmission and current source Im to start for the capacitor, the potential difference between the two ends increases linearly beyond the one reference = reference voltage L, the voltage comparator CPm is touched = the holding time MX is changed from the low level to the A The maintenance termination signal is turned to the return level. Therefore, the ore π of the maintenance time T is determined by the maintenance time control unit 36_3. The length of Fig. 7 (8) shows the circuit diagram of the second real circuit 73 according to the present invention. Fortunately, the load control power is the same as the first embodiment. The example is the maintenance time control unit μ.

The light load variation of the Rx is triggered by the private hopper # ’, rising, and the winter stop signal is maintained at the time Tm. Therefore, in the second embodiment, reference is made to Fig. 7 (8), which occurs only after the rising phase. In the electric power reduction, .../ rise phase, that is, from time " to... Motor 1L rises linearly from valley 1 to peak I, that is, from time t2 5 , ., Pk. While maintaining the phase energy, t g t , the inductor current IL is maintained at almost constant sorrow, that is, it is maintained at time 疋 from time t3 to t4 ^ Pk. In the down phase,

Ibm. The inductor current 1L linearly decreases from the peak value iPk to the valley value. Figure 8(A) shows the lightning loss according to the originator's road 83. The light-load control of the third yoke case is different from the third embodiment. - The embodiment lies in the control with the second trigger: the early 86-3 has the first trigger end AT! A〇2. The first-touch and the output end a(1) and the second output start _ = ΑΤΊ are triggered by the rising end signal RX, and the first first sustain time T. Slave m Chu The first round of the exit A0] private mountain # m,, two brothers - after the time Tml, the rain to the first maintenance termination signal Μχι. Therefore, in the light load mode of 19 1278171 = embodiment, the 'maintenance phase is tied 1 W and then occurs. The second trigger terminal ΑΤ2 is triggered by the two rising, and starts to calculate the second maintenance 1...x..., the second round of the output A02 is the maintenance time. Therefore, in the light load mode of the third embodiment, = Just MX2. Continued after the decline phase. The younger brother, the pre-holding phase is connected with reference to Figure 8(B). In the ascending phase, the inductance (4) is also p from time u to... The resistance Πη linearly rises to the peak period, that is, from the time t2 ^ Tp & Inductor current iL is held in an almost fixed state, that is, it is maintained at time, that is, from time Ut4, inductance p is in the falling phase, and value W is in the second maintenance (four). To the valley Lu Fu 丨 white long, that is, from time t4 flow IL maintained at almost fixed energy, inductance J. The heart's, that is, the valley value ibm maintained at time t4. Although the purple p#, i-hunting of the present invention is exemplified by the preferred embodiment, it should be understood that the present invention is not a § brother. , ^ t disclosed embodiments herein. On the contrary, the present invention is intended to cover various modifications and similar configurations that are apparent to those skilled in the art. According to the most comprehensive interpretation, the scope of the patent application scope should be such that there are such modifications and similar configurations. [Simple description of the diagram] Figure 1 shows the unseen upgrade. Figure 2 (4) shows the circuit diagram of the converter. In the light load mode of Baizhi, the timing of the inductor current 20 Ϊ 278171 Fig. 2 (8) shows the operating state of the synchronous switching circuit in the rising phase. Figure 2 (C) shows the synchronous switching. Operational state in the falling section Fig. 3 shows a circuit diagram of the 篦_ according to the present invention. See the step-up voltage converter of the beta column. Figure 4 shows the timing diagram of the first (four) voltage (four) and inductor current in accordance with the present invention. ΛΤ Figure 5(A) shows the synchronous switching circuit. schematic diagram. 1 Self-only state Figure 5 (B) shows the operation of the synchronous switching circuit in the falling phase. Figure 5 (C) shows the synchronous switching circuit in the maintenance diagram. Operation Status Operation in the Stage Status Operation Figure 5(D) shows a schematic diagram of the state of the synchronous switching circuit during sleep. Figure 6 shows a detailed circuit diagram of the first in accordance with the present invention. The maintenance time control unit of the second embodiment The light load control system of the second embodiment The light load mode of the second embodiment The light load control circuit of the third embodiment Fig. 7(A) shows the circuit diagram of the first circuit according to the present invention. Fig. 7(B) shows a timing chart of the inductor current in accordance with the present invention. Figure 8 (Α) shows a road map of the 21st 1278171 road according to the present invention. 'β Figure 8(B) shows a timing chart of the inductor current in the light load mode according to the third embodiment of the present invention. [Main component symbol description] 10, 30 synchronous switching circuit 11,31 lifting control circuit 12, 32 driving circuit

1 3, 33, 73, 83 light load control circuit 34 voltage feedback circuit 35 start unit 36, 76, 86 stage control unit 36-1, 36-2 current comparator 36-3, 76-3, 86-3 maintain Time control unit 37 sleep control unit 50 load AT, ATI, ΑΤ2 trigger terminal AO, AO1, A02 output terminal Bm buffer inverter C〇ut output capacitor cm capacitance CPm voltage comparator D1 ~ D4 drive signal L inductor 22

Claims (1)

Ln 9 ^__| \\^A\ . |〇C7rvC.5 1278171 Noisy 4117 at the end of the tenth, the scope of the patent application · · · Light load control lightning path is right ^, used to control a switching circuit, Switching the terminal to - input voltage and ::::: to:; sex::-inductance-inductive-selectively combines the inductance of the inductor - the _ end to the first: the switching unit, the ground, the light The load control circuit package::...outputs the power and the logic one-stage control unit, and uses the segment to ^^, so that the switching circuit operates in a plurality of stages and each of the several stages of the cycle has: = rising phase 'To make the inductor current flowing through the inductor rise, · down ~ I5 from # again, so that the inductor current drops; and - the sustain phase, so that the inductor current is maintained almost fixed, and the sleep control unit, used in the sleeper Lei 十 十 ATM ® 私 建 建 建 = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Both of them are in the middle. 2. The control circuit according to item (4) of claim 1 wherein: 4 the falling phase occurs after the rising phase, and the maintaining phase occurs after the falling phase. ζ 3. The light load control circuit of claim i, wherein: the maintenance phase occurs after the rising phase, and the falling phase occurs after the maintaining phase. 24 1278171 No._0, No. 11741^, Huili applied for Zaimin Liyue 18 I 〇v敝) Replacement page 丨4 · For example, the light load control circuit of the patent scope is one of the items, in which the maintenance phase is divided into a first maintenance phase and a second maintenance phase, such that: the first maintenance phase occurs after the rising phase; the falling phase occurs after the first maintenance phase and the second maintenance phase occurs After the decline phase. 5. The light load control circuit of claim 3, wherein the duration of the sustain phase is proportional to the input voltage. 6. The light load control circuit of claim i, wherein: in the rising phase, the input is switched, and the X + waste α is coupled to the ground. Early, the second end of the brother is coupled to the light load control circuit of the logic I, such as the second f patent range, the logical connection, and the three-person switching unit is used to make the first end meet the voltage . The money "change unit makes the second-integration to the round 8" as in the patent application range in the maintenance phase, the logic ground, and the output ground. The input switching unit causes the 丄1 to couple from the end of the mouth The switching unit couples the second end to 5 to the logic 25 1278171 gM94117416 Patent Application 9 · As claimed in the patent scope] tS >& a & The control unit of the stage has a first comparator, and the inductor current is reached by the inductor current and a predetermined peak 4 to reach the peak current. ^Bundle in the 1 0 · If the patent application is a target (5) The light load control circuit has a control unit with a / / medium inductor current and a predetermined valley value for comparing the inductor inductor current to the valley current = ^ the falling phase ends at the η. The light load control circuit, the control unit of the stage has a time control unit for holding the time occupied by the stage. The dimension is determined. 12. The light load control circuit of the first item of the patent scope, dragon φ. sleep During the period, the input switching unit one: the middle input voltage 'and the output switching unit makes the first coupling: potential. ^ is in a foreign motion 13. As in the patent scope of the item [light load control circuit, During the sleep period, the input switching unit makes a "medium" bit logically, and the output switching unit causes the coupling to be coupled to a floating electric 26 1278171 repair ('more wind I Patent No. 0_94117416 Shen Qing € 14 · If the patent application range is in the sleep period, the floating potential, and the round-out voltage. a light load control circuit, the turn-in switching unit causes the first switching unit to couple the second end, wherein: the end is at - to the round 1 5 · If the scope of the patent application is during the sleep period, the floating potential, and the wheel is out of the ground. An autumn spur circuit, wherein the = input switching unit causes the first end to switch the second end face to the switching unit:: 16 • as claimed in the sleep period, the logically, and the round Ground. 1 7 · If the scope of the patent application is in the sleep period, the floating potential, and the turn-out potential. The light load control circuit of the first item is in the middle. The input switching unit causes the first end prescription to switch the early element so that the second end is in another switching mode, the π circuit is a switching circuit, and the circuit has one Input switching 罝; ^ One end to one round into the Lei 咖 ^ ^ ^ 伴 伴 — — — — — — — — — — — — — — — — — 电感 电感 电感 电感 电感 电感 电感 电感 电感 电感 电感 电感 电感 电感 电感 电感 电感 电感 电感 电感 电感 电感In a second series, the light load control circuit includes: the output electric dust is 70 degrees earlier than the logic segment, so that the switching circuit operates in a plurality of stages, each of the plurality of stages of the cycle Having a potential difference and: in the first stage, between the (four)-end and the (four) two-end, the packet difference has a dipole-polarity; the potential...the two-stage' is made across the first-end and the second end The second polarity is opposite to the first polarity, and the second phase is such that the difference between the first end and the second end is substantially zero. And 3 Haiyi sleep control unit, used to achieve one at the output::: electric mountain pressure After -, so that the switching circuit operates in a sleep period while the anti = Μ brother one end and the second end both are coupled to the input pressure, and the pressure in any one of the logically. The power supply control circuit of 19. The light load control circuit of claim 18, wherein the second phase occurs after the first phase, and the third phase occurs after the second phase. 20. The light load control circuit of claim i8, wherein the third phase occurs after the first phase and the second phase occurs after the third phase. 28 1278171 No. 0941174] Patent Application No. 6 - 1 September 18 repair (more) positive: type, = down voltage converter, operating in - first mode and - second - inductance:: ί: end: The input-switching unit is configured to selectively couple the switching 罝-, the input voltage and the - logic ground, and the - round-out, where the first end of the inductor is selectively coupled to the voltage and the logic ground; Knowing that an output electric drive circuit is used, P, < is used to drive the switching circuit; - lifting control t-road lightning modification; 4 丨 for the arsenal through the smuggling;: and:: the switching circuit, so that The input voltage is converted into the wheel: a circuit: an L negative I-load control circuit for following a number of steps r through the drive in the second mode;:: changing the circuit' so that the switching circuit alternately operates in Fubaifeng During the period of % and one sleep, wherein: each of the plurality of phase cycles has: liter; - the rising phase, such that the inductor current flows through the inductor and the falling phase causes the inductor current to drop; and the sustain phase Keeping the inductor turbulence almost fixed, During the sleep period, the first end and the second end 8a are prevented from being turned into a thunder, indicating that the output voltage and the logic ground are both coupled. A lift-type voltage converter of the scope of claim 2, wherein the application of the drop phase occurs after the rising phase, and the maintenance phase occurs after the falling phase. 23. The lift-down voltage converter of claim 21, wherein the maintaining phase occurs after the rising phase and the falling phase occurs after the maintaining phase. A step-up voltage converter, operating in a first mode and a 24th mode, comprising a switching circuit having a round of intent to speak - _ negative intrusion switching early for selective-inductance - a first end to an input voltage and a logic ground, and an input: a switching unit for selectively engaging one of the second ends of the inductor: a voltage and a logic ground; a powder output driving circuit for driving the a switching circuit; a 〃-lift control circuit for converting the input voltage into the wheel-light-load control circuit via the switch circuit in the _th mode for controlling the second circuit The switching circuit is configured to cause the switching circuit to be operated by the driving phase cycle and a sleep period, and 9 again: each of the plurality of phase cycles has: a first phase, making the first phase — The potential difference has a first polarity; 鳊一》Haidi one of the ends of the 30 1278171 No. 941174丨6 patent is run by the slaughter After replacement, there is no line to replace the Zen- a potential difference; and a second polarity, the second polarity being opposite to the first pole to the third phase such that the difference across the first potential is substantially zero; The sleep period between one end and the second end prevents the first end and the second end from being respectively coupled to the side input voltage, the output voltage, and either of the logic grounds. 5. The lift-down voltage converter of claim 24, wherein the second phase occurs after the first phase, and the third phase occurs after the second phase. 26. Where the lift voltage is chopped as in paragraph 24 of the scope of claim 4, the third phase occurs after the first phase, and the second phase occurs after the third phase. 31