CN101938212A - Low-voltage start-up circuit and boost converter - Google Patents
Low-voltage start-up circuit and boost converter Download PDFInfo
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- CN101938212A CN101938212A CN 200910088048 CN200910088048A CN101938212A CN 101938212 A CN101938212 A CN 101938212A CN 200910088048 CN200910088048 CN 200910088048 CN 200910088048 A CN200910088048 A CN 200910088048A CN 101938212 A CN101938212 A CN 101938212A
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Abstract
The invention relates to the field of electricity. In order to solve the problems of high low voltage start-up cost and unreliability which are caused by low power supply voltage in the prior art, the invention provides a low-voltage start-up circuit and a boost converter. The low-voltage start-up circuit comprises an oscillator, a converting unit and a clock boost unit, wherein the oscillator is used for generating a clock signal for turning on or turning off the converting unit; the converting unit is used for realizing the conversion between input voltage and output voltage; and the clock boost unit is used for boosting the voltage amplitude of the clock signal outputted by the oscillator to drive the converting unit. After the boost converter is started by utilizing the low-voltage start-up circuit, the start-up circuit is turned off, and the converter is regulated to enter the stable operating state. The embodiment of the invention has the advantages of improving the voltage amplitude of the inputted clock signal quickly so as to start the low-voltage start-up circuit or the boost converter quickly, along with simple structure and low realization cost.
Description
Technical field
The present invention relates to electricity field, particularly a kind of low voltage start circuit and boosting type converter.
Background technology
Boosting type converter is widely applied in the portable product at present.Usually the power supply of portable product adopts battery to power as power supply, requires the boosting type converter can be at lower working power steady operation.
Be illustrated in figure 1 as booster type DC/DC convertor circuitry figure of the prior art.The direct driving switch pipe of oscillator clock signal.Common battery is 1.2 volts of voltages, and when supply voltage (for example is lower than 0.7V) under lower condition, to 0.7V, can't open or weak unlatching switching tube by the high level of drive source (0.7V) at 0.65V for the common cut-in voltage of switching tube.After system powers on, from input power supply V
INConversion and the energy that stores output capacitor into less than the startup stage integrated circuit energy that consumes, cause the voltage Vout on the output capacitor can't continue to raise, cause the system start-up failure.
Along with the application in the low-voltage condition of boosting type converter increases, require the startup supply voltage V of boosting type converter on the properties of product
INBe no more than 0.8V (even not surpassing 0.6V).Therefore, prior art as shown in Figure 1 adopts oscillator output can't satisfy application demand to boosting type converter as the method for start-up circuit drive source.
A kind of boosting type converter has been proposed in U.S. Patent number US5247239, when supply voltage is lower than switching tube cut-in voltage Vth, switching tube turn-offs, can't charge to inductor, inductor can't energy reserve and can't be released energy to output, output voltage V out can't promote, and causes thrashing.Except not supporting that more low supply voltage starts in addition down, in order to realize the start-up control and the control in two stages of FEEDBACK CONTROL, system is respectively to these two working stage configurations, two cover booster circuit (switching tubes, the booster circuit that inductor and Schottky diode constitute), use two inductors and two diodes, greatly increased the application cost of this boosting type converter.
Chinese patent application numbers 200310123992 discloses a kind of method that reduces the starting resistor of boost converter, and this technology is started with from the starting resistor angle that reduces boost converter, in theory the starting resistor of minimum is reduced near the switching tube cut-in voltage Vth.Yet when supply voltage is reduced to below the switching tube cut-in voltage Vth, the switching tube in the start-up circuit turn-offs, and can't charge to inductor, can't promote output end voltage, finally causes starting failure.This technology can't further reduce starting required supply voltage, promptly is reduced to below the switching tube cut-in voltage Vth, realizes the normal startup of system.
Summary of the invention
The embodiment of the invention provides a kind of low voltage start circuit and boosting type converter, is used to accelerate the converter circuit toggle speed, and further reduces the startup supply voltage.
The embodiment of the invention has proposed a kind of low voltage start circuit, comprises oscillator, and converting unit also comprises the clock boosting unit;
Described oscillator is used to produce the clock signal of the described converting unit of switch;
Described converting unit is used to realize the conversion of input voltage-output voltage;
Described clock boosting unit is used to promote the voltage amplitude of described oscillator clock signal, to drive described converting unit.
A further aspect according to the described a kind of low voltage start circuit of the embodiment of the invention, also comprise the power supply detecting unit, be used to detect import described oscillator when starting supply voltage whether less than predetermined threshold value, if less than described threshold value then start described clock boosting unit; Otherwise close described clock boosting unit, directly the clock signal converting unit that described oscillator is exported is to described converting unit.
Another further aspect according to the described a kind of low voltage start circuit of the embodiment of the invention, the power supply of described low voltage start circuit is connected with the output of described input power supply or described low voltage start circuit, and the output of described low voltage start circuit has an initial value.
According to another further aspect of the described a kind of low voltage start circuit of the embodiment of the invention, described clock boosting unit comprises: charge pump unit, voltage clamp unit and gate circuit unit;
Described charge pump unit is used for the level amplitude rising with the clock signal of described input, thereby promotes the high level amplitude of described clock signal;
Described voltage clamp unit is used to detect the level of charge pump unit output voltage (Vcp), when Vcp greater than according to input power supply (V
IN) voltage or output voltage V out set the level amplitude time, drive the described clock signal of the shielding input charge pump unit that pulls down switch in the described gate circuit unit, make charge pump unit stop to boost; When described Vcp is less than or equal to described according to input power supply V
INVoltage set the voltage level amplitude time, recover the clock signal of the described charge pump unit of input again, described charge pump unit is restarted;
Described gate circuit unit is used for the receive clock signal.
Another further aspect according to the described a kind of low voltage start circuit of the embodiment of the invention, the signal that described gate circuit unit receives also comprises the selection signal, this selection signal is the startup of described power supply detecting unit input or the signal of closing described clock boosting unit, described gate circuit unit is selected signal according to this, stops or recovering described charge pump described clock signal is made boosting inverter.
The embodiment of the invention also provides a kind of boosting type converter in order to solve the problems of the prior art, comprises feedback control unit, also comprises low voltage start circuit;
Described low voltage start circuit comprises:
Oscillator is used to produce the clock signal of the described converting unit of switch;
Converting unit is used for conducting or closes the output of described low voltage start circuit;
The clock boosting unit is used to promote the voltage of described oscillator clock signal, to import described converting unit;
Described feedback control unit is used to realize the output of described low voltage start circuit, starts or closes described low voltage start circuit, and utilize the output of described low voltage start circuit to power to the external world.
A further aspect according to the described a kind of boosting type converter of the embodiment of the invention, described low voltage start circuit also comprises: the power supply detecting unit, be used to detect import described oscillator when starting supply voltage whether less than predetermined threshold value, if less than described threshold value then start described clock boosting unit; Otherwise close described clock boosting unit, directly export described oscillator output signal converting unit to described converting unit.
Another further aspect according to the described a kind of boosting type converter of the embodiment of the invention, the power supply of described low voltage start circuit is connected with the output voltage of described input power supply or described low voltage start circuit, and the output voltage of described low voltage start circuit has an initial value.
According to another further aspect of the described a kind of boosting type converter of the embodiment of the invention, described clock boosting unit comprises: charge pump unit, voltage clamp unit and gate circuit unit;
Described charge pump unit is used for the level amplitude rising with the clock signal of described input, thereby promotes the high level amplitude of described clock signal;
Described voltage clamp unit is used to detect the level of charge pump unit output voltage (Vcp), when Vcp greater than according to input power supply V
INVoltage or output voltage V out set the level amplitude time, drive the described clock signal of the shielding input charge pump unit that pulls down switch in the described gate circuit unit, make charge pump unit stop to boost; When described Vcp is less than or equal to described according to V
INDuring the voltage level amplitude set, recover the clock signal of the described charge pump unit of input again, described charge pump unit is restarted;
Described gate circuit unit is used for the receive clock signal.
Another further aspect according to the described a kind of boosting type converter of the embodiment of the invention, the signal that described gate circuit unit receives also comprises the selection signal, this selection signal is the startup of described power supply detecting unit input or the signal of closing described clock boosting unit, described gate circuit unit is selected signal according to this, stops or recovering described charge pump described clock signal is made boosting inverter.
The embodiment of the invention can improve the voltage clock signal of input fast, makes low voltage start circuit or boosting type converter start fast, the boosting type converter of support performance simultaneously under low supply voltage more, and simple in structure, realize that cost is low.
Description of drawings
In order to be illustrated more clearly in the embodiment of the invention or technical scheme of the prior art, to do to introduce simply to the accompanying drawing of required use in embodiment or the description of the Prior Art below, apparently, accompanying drawing in describing below only is some embodiments of the present invention, for those of ordinary skills, under the prerequisite of not paying creative work, can also obtain other accompanying drawing according to these accompanying drawings.
Fig. 1 is booster type DC/DC convertor circuitry figure of the prior art;
Fig. 2 is the structural representation of a kind of low voltage start circuit of the embodiment of the invention;
Fig. 3 is the structural representation of a kind of boosting type converter of the embodiment of the invention;
Fig. 4 is another structural representation of a kind of boosting type converter of the embodiment of the invention;
Fig. 5 a is depicted as embodiment of the invention clock boosting cellular construction schematic diagram;
Fig. 5 b is the sequential chart of the embodiment of Fig. 5 a clock boosting unit 125;
Fig. 6 is an embodiment of the invention charge pump unit structural representation;
Fig. 7 is the structural representation of the voltage clamp unit in the clock boosting unit in the embodiment of the invention;
Fig. 8 is the structural representation of embodiment of the invention power supply detecting unit;
Fig. 9 is boost converter one output waveform figure in the prior art;
Figure 10 is the startup figure as a result of embodiment of the invention boost converter;
Figure 11 is a boost converter output waveform figure in another prior art;
The startup that Figure 12 shows that another boost converter of the embodiment of the invention is figure as a result.
Embodiment
Below in conjunction with the accompanying drawing in the embodiment of the invention, the technical scheme in the embodiment of the invention is clearly and completely described, obviously, described embodiment only is the present invention's part embodiment, rather than whole embodiment.Based on the embodiment among the present invention, those of ordinary skills belong to the scope of protection of the invention not making the every other embodiment that is obtained under the creative work prerequisite.
Be illustrated in figure 2 as the structural representation of a kind of low voltage start circuit of the embodiment of the invention.
Described oscillator 201 is used to produce the clock signal of the described converting unit 202 of switch.
Described converting unit 202 is used for the conversion of input supply voltage to described low voltage start circuit output voltage.
Described clock boosting unit 203 is used to promote the clock signal level amplitude of described oscillator 201, exports described converting unit 202 to.
As one embodiment of the present of invention, also comprise the power supply detecting unit, be connected with described clock boosting unit 203, whether supply voltage sets threshold value less than one when being used for detecting startup, if less than described threshold value then start described clock boosting unit 203, otherwise close described clock boosting unit 203, directly the clock signal that described oscillator 201 is exported is to described converting unit 202.Wherein said oscillator 201 also obtains the power supply of described power supply, and the high level of the clock signal of output is described input power supply V
IN
Be illustrated in figure 3 as the structural representation of a kind of boosting type converter of the embodiment of the invention.
Low voltage start circuit 40 comprises N type switching tube 41, clock boosting unit 125, oscillator 100, power supply detecting unit 130 and Schottky diode 42.Wherein N type switching tube 41 and Schottky diode 42 constitute above-mentioned converting unit, in this example to input power supply V
INVoltage carry out exporting Vout after the boost conversion.The drain terminal of described N type switching tube 41 is connected to input power supply V at the LX end by inductor L1
IN, shown in input power supply V
INAs the power supply of low voltage start circuit 40, be expressed as power supply V in the drawings
DDDescribed Schottky diode 42 negative electrodes are connected to the output end vo ut of described boosting type converter.The drain terminal of described N type switching tube 41 is held the anode of linking described Schottky diode 42, the source terminal ground connection of described N type switching tube 41 at LX.Described clock boosting unit 125 links to each other with oscillator 100, link to each other with the grid of described N type switching tube 41, the startup stage, it makes multiplication back output signal BCLK to level amplitude of the clock signal clk of described oscillator 100.
Whether the output of described power supply detecting unit 130 links to each other with described clock boosting unit 125, adjudicate described clock boosting unit 125 and the level amplitude of described oscillator clock signal CLK is operated.
As input power supply V
INThe set point that detects less than power supply of voltage and less than the cut-in voltage Vth of described N type switching tube 41, for example V
INBe 0.5V, the reference value of the setting that power supply detects is 1.5V, and the cut-in voltage Vth of described N type switching tube 41 is 0.7V, described V
DDVoltage less than the reference value 1.5V of described setting, then starting described clock boosting unit 125 utilizes the level amplitude of the clock signal clk of the 125 pairs of oscillators in this clock boosting unit, 100 inputs to promote, as driving described N type switching tube 41 clock signal BCLK owing to the level amplitude promotes, its high level amplitude V
IH=K*Vin, K are multiplication constant, V
IIICut-in voltage Vth much larger than described N type switching tube 41.Because after the driving voltage of described N type switching tube 41 was boosted, this N type switching tube 41 was fully opened, input power supply V
INThe electric current that flows out carries out energy storage to inductor L1 charging at described inductor L1, and inductor L1 charges to output capacitor by described Schottky diode 42 again, promotes output voltage V out, and the converting unit that N type switching tube 41 grades are formed realizes input power supply V
INVoltage to the conversion of described low voltage start circuit output voltage V out, realize that the start-up circuit under the low supply voltage condition more normally starts.In addition, after drive clock signal level amplitude promotes, in each clock cycle, inductor L1 charging current is also significantly promoted, increased the energy storage on the single clock cycle internal inductance device L1, inductor L1 also increases to the energy of the transfer of output capacitor, the output end voltage hoisting velocity is fast than prior art, effectively shortens the start-up time of transducer.
As input power supply V
INVoltage during greater than the reference value of a setting of power supply detecting unit 130, described power supply detecting unit 130 does not start described clock boosting unit 125, the clock signal clk that described oscillator 100 is imported is directly inputted to the grid of N type switching tube 41, and the converting unit of forming by these N type switching tube 41 grades realizes input power supply V
INVoltage to the conversion of described low voltage start circuit output voltage V out, this clock signal amplitude is much larger than the cut-in voltage Vth of driving N type switching tube 41, start-up circuit 40 is realized normal the startup.
In the start-up course, when described feedback control unit 200 detected output voltage V out and reaches predetermined threshold, for example Vout reached 1.8V, and feedback control circuit unit 200 judges that start-up circuits 40 finish, and send Ngate signal and STEND signal.After starting end, the Ngate signal is conducting or shutoff N type switching tube 601 under feedback control unit 200 controls, the STEND signal controlling is closed the work of described low voltage start circuit 40 and the output signal BCLK of clock boosting unit 125 is a low level, and it is continuous to extraneous power devices to utilize transducer output Vout to support by described feedback control unit 200.After low voltage start circuit 40 was closed, the output that feedback control unit 200 is regulated described boosting type converter entered stable state.
When starting, because described output voltage V out is not when arriving described predetermined threshold, the startup stage that described low voltage start circuit 40 being operated in always.
Be illustrated in figure 4 as another structural representation of a kind of boosting type converter of the embodiment of the invention.
Low voltage start circuit 40 comprises N type switching tube 41, clock boosting unit 125, oscillator 100 and Schottky diode 42, and wherein N type switching tube 41 and Schottky diode 42 constitute above-mentioned converting unit.The drain terminal of described N type switching tube 41 is connected to input power supply V at the LX end by inductor L1
INThe anode tap of described Schottky diode 42 is connected to the LX end of described inductor L1, and cathode terminal is connected to the output end vo ut of described boosting type converter, and described output voltage V out is connected to the power supply V of described low voltage start circuit 40
DD, described output voltage V out has an initial value.The drain electrode process LX of described N type switching tube 41 links the anode of described Schottky diode 42, the source end ground connection of described N type switching tube 41.Described clock boosting unit 125 links to each other with oscillator 100, link to each other with the grid of described N type switching tube 41, the startup stage, the level amplitude of the clock signal clk of described oscillator 100 is made multiplication back output signal BCLK.
Very low and when supply voltage less than the cut-in voltage Vth of described N type switching tube 41, drive described N type switching tube 41 clock signal high level amplitudes and promote, wherein high level amplitude V
IH=K*Vout, K are multiplication constant.Raising along with output voltage V out level amplitude, the output clock level amplitude of described oscillator 100 also improves, the raising of also doubling of the level amplitude of the output clock BCLK of clock boosting unit 125, output voltage V out like this, described oscillator 100 and described clock boosting unit 125 constitute a regenerative feedback loop that promotes output voltage V out, Vout is promoted fast, realize normally starting under the low-voltage.For example, the input power supply V of 0.7V
INThe forward junction pressure drop 0.1V of Schottky diode, suppose K=2, the high level amplitude of clock boosting unit 125 drive clock signals is about 1.2V so, usually the cut-in voltage Vth of N type switching tube 41 is that 0.6V is to 0.7V, fully described N type switching tube 41 unlatchings of assurance realize the accumulation of electrical current of inductor L1 and in inductor L1 energy storage, inductor L1 passes through Schottky diode 42 again to output capacitor charging and raising output voltage V out.Finally under the low-voltage condition, finish the start-up course of boosting type converter.In addition, after drive clock signal level amplitude promotes, in each clock cycle, inductor L1 charging current is also significantly promoted, increased the energy storage on the single clock cycle internal inductance device L1, inductor L1 also increases to the transfer of the energy of output capacitor, the output end voltage hoisting velocity is fast than prior art, has shortened the start-up time of transducer.
After startup is finished, when output voltage V out reaches predetermined threshold, for example during 1.8V, described feedback control unit 200 is to described oscillator 100 output control signal of telecommunication STEND, stop described low voltage start circuit 40 and described clock boosting unit 125 output signal BLCK are high impedance status, by described feedback control unit 200 output signal Nage driving switch pipes 41, utilize converter output voltage Vout to continue to extraneous power devices.After low voltage start circuit 40 was closed, the output that feedback control unit 200 is regulated described boosting type converter entered stable state.
In the start-up course, if when described output voltage V out does not arrive described predetermined threshold, the startup stage that described low voltage start circuit 40 being operated in always.
Be depicted as embodiment of the invention clock boosting cellular construction schematic diagram as Fig. 5 a.
Comprise charge pump unit 60 in the clock boosting unit 125, voltage clamp unit 62 and gate circuit unit 61.
Described charge pump unit 60 is used for the level amplitude rising with the clock signal of described input, thereby promotes the voltage of described clock signal.
Described voltage clamp unit 62 is used to detect the level of charge pump unit output voltage V cp, when Vcp surpasses according to input power supply V
INVoltage set a reference level amplitude time, V for example
INBe 1.2V, the reference level amplitude of setting is 1.9V, when the Vcp level is higher than 1.9V, described voltage clamp unit 62 drive the described charge pump unit 60 of shielding that pulls down switch input clock signal (φ ck,
), make charge pump unit 60 stop boost action; Descend and be no more than up to Vcp according to input power supply V
INAfter the reference level amplitude of setting, discharge again described charge pump unit 60 input clock signal (φ ck,
), described charge pump unit 60 restarts.
Described gate circuit unit 61 is used for the receive clock signal.Wherein the input signal of gate circuit unit 61 can also comprise selecting signal BCKSEL, this selection signal to be used for power supply detecting unit 130 judges whether start described clock boosting unit 125.
Described clock boosting unit 125 improves the level amplitude of oscillator 100 input clock signals, be converted to the grid that BCLK exports to N type switching tube 41, as Fig. 5 b is the sequential chart of the embodiment of Fig. 5 a clock boosting unit 125, input clock signal CLK is through boosting variation, output signal BCLK, its high level amplitude K*V that doubles in theory
IN, K is the coefficient that boosts.
As Fig. 6 is embodiment of the invention charge pump unit structural representation.
As figure is the charge pump unit circuit of four sections Dickson structures, adopts the non-overlapping clock of two-phase CLK,
Continuous to following voltage node 1 → 2 → 3 → 4 → Vout step by step capacitor C 1, C2, C3, the course of work that C4, Cout charge-boost finally produces regulated output voltage Vout.The non-overlapping clock of described two-phase CLK,
Produce drive clock V φ by driving inverter,
Below be charge pump circuit in the course of work in a work clock cycle, and each clock cycle is divided into two stage S1, S2.
In the S1 stage,
Be high level, V φ is a low level, and the grid of transistor MD1-drain voltage Vgs1 is greater than the cut-in voltage Vth of transistor MD1, and transistor MD1 conducting is from power supply V
DDCapacitor C 1 charging that the electric current that flows out flows through transistor MD1 and node 1 is linked to each other, the voltage difference Vc1 on capacitor C 1 positive/negative plate of charging back is approximately equal to V
DD-Vth, this moment, the electromotive force V1 of node 1 also equaled V
DD-Vth; Enter S2 during the stage,
Be low level, V φ is a high level, and voltage difference Vc1 remains unchanged on the capacitor C 1, and when V φ is a high level, capacitor C 1 negative plate current potential becomes V so
DD, the electromotive force V1 at node 1 place carries and is elevated to V
DD+ V
C1=V
DD+ (V
DD-Vth)=2V
DD-Vth.Identical operation principle, the gate source voltage Vgs2 (Vgs2=2V of transistor MD2
DD-Vth) greater than a cut-in voltage Vth, transistor MD2 conducting to node 2 continuous capacitor C 2 chargings, equals gate source voltage up to VC2 and deducts cut-in voltage Vth, i.e. a 2V
DD-2Vth.The rest may be inferred, with voltage difference V on the capacitor C 3 that node 3 links to each other
C3Change to 3V
DD-3Vth, the voltage difference C4 electromotive force that node 4 links to each other rises to 4V
DD-4Vth ... drive through the non-overlapping clock of two-phase, C4 produces 5V
DDThe electromotive force of-4Vth and to output capacitance Cout charging, final Vout is stabilized in 5V
DD-5Vth realizes from power supply V
DDArrive the voltage multiplication of output voltage V out, but have the loss of turn on voltage threshold Vth in the output voltage multiplicative process.
Fig. 7 is the structural representation of the voltage clamp unit 62 in the clock boosting unit in the embodiment of the invention.In the present embodiment with input power supply V
INBe reference voltage, charge pump unit output voltage V cp is as detected voltage, as described reference voltage V
INAnd the voltage difference between the described detected voltage Vcp is greater than the cut-in voltage of transistor 65 | Vthp|, transistor 65 conductings, there is electric current to flow through transistor 65 and resistance R 1, and C1 charged, behind the cut-in voltage Vth of capacitor C 1 current potential greater than transistor 66, transistor 66 with drop-down and its drain terminal node PDWN to low level, the input drive signal of charge pump 60 is along with node PDWN drags down, charge pump 60 also stops boost action, Vcp voltage no longer continues to rise like this, and its voltage swing is continued to promote by 62 restrictions of voltage clamp unit.When Vcp voltage reduces, transistor 65 is closed in the voltage clamp circuit 62, and transistor 66 ends, and just removes drop-down to the input clock signal of charge pump, and charge pump 60 recovers boost action and also promotes output voltage V cp.
Be illustrated in figure 8 as the structural representation of embodiment of the invention power supply detecting unit.
By to R1, apply input power supply V on the resistance string that R2 and R3 constitute
IN, detect voltage V
IN* R2/ (R1+R2+R3), with its device 301 positive input voltage relatively as a comparison, another reference voltage that is made of built-in reference current and resistance is the negative input voltage of device as a comparison, comparator 301 output signals are exported BCKSEL by buffer, deliver to the grid of transistor MP1 simultaneously, it sets comparator 301 hysteresis voltage width by the voltage difference on the R3, prevents the interference of noise to comparator output.When positive input voltage was lower than negative input voltage, output BCKSEL was a low level, and the expression supply voltage is above setting voltage; When positive input voltage was higher than negative input voltage, output BCKSEL was a high level, represents that supply voltage is higher than setting voltage.As shown in Figure 3, described power supply detecting unit 130 output signals are delivered to described clock boosting unit 125, and output signal is a low level, and the level amplitude of the 125 pairs of described oscillators 100 in described clock boosting unit increases, and improve the voltage of clock signal; Output signal is a high level, and the level amplitude of the 125 pairs of described oscillators 100 in described clock boosting unit keeps former level amplitude output.
By the above embodiments, be illustrated in figure 9 as boost converter output waveform figure in the prior art, abscissa is a time shaft, ordinate is output signal (voltage).Fig. 9, when system's enable signal (SHDN) when being high, the startup stage that boost converter entering, output voltage has reached setting voltage through long uphill process, and start-up time is about 1.6ms.Start figure as a result for embodiment of the invention boost converter as shown in figure 10, under same low voltage conditions, the boosting type converter of the embodiment of the invention has been realized normal startup, and promote the level amplitude of output end voltage faster, can improve the voltage clock signal of input fast, make low voltage start circuit or boosting type converter start fast.
Under the condition of the cut-in voltage Vth that is lower than switching tube, cut-in voltage Vth=0.95V, Vin=0.9V, Figure 11 are boost converter output waveform figure in another prior art, are output waveform figure after the startup of embodiment of the invention boost converter as shown in figure 12.Prior art is being lower than startup failure under the switching tube cut-in voltage Vth, and the present invention program has realized normal startup under the same conditions.The embodiment of the invention realizes the startup under the low supply voltage more or the application of boost converter, has expanded the power supply scope of application, and simple in structure, realizes that cost is low.
One of ordinary skill in the art will appreciate that all or part of flow process that realizes in the foregoing description method, can instruct relevant hardware to finish by computer program, described program can be stored in the computer read/write memory medium, this program can comprise the flow process as the embodiment of above-mentioned each side method when carrying out.Wherein, described storage medium can be magnetic disc, CD, read-only storage memory body (Read-Only Memory, ROM) or at random store memory body (Random Access Memory, RAM) etc.
Above-described embodiment; purpose of the present invention, technical scheme and beneficial effect are further described; institute is understood that; the above only is the specific embodiment of the present invention; and be not intended to limit the scope of the invention; within the spirit and principles in the present invention all, any modification of being made, be equal to replacement, improvement etc., all should be included within protection scope of the present invention.
Claims (10)
1. a low voltage start circuit comprises oscillator, and converting unit is characterized in that also comprising the clock boosting unit;
Described oscillator is used to produce the clock signal of the described converting unit of switch;
Described converting unit is used to import the conversion of power source voltage to the voltage of described low voltage start circuit output;
Described clock boosting unit is used to promote the voltage amplitude of described oscillator clock signal, to drive described converting unit.
2. a kind of low voltage start circuit according to claim 1, it is characterized in that, also comprise the power supply detecting unit, be used to detect import described oscillator when starting supply voltage whether less than predetermined threshold value, if less than described threshold value then start described clock boosting unit; Otherwise close described clock boosting unit, directly export described oscillator clock signal to described converting unit.
3. a kind of low voltage start circuit according to claim 1, it is characterized in that, the power supply of described low voltage start circuit is connected with the output of described input power supply or described low voltage start circuit, and the voltage of the output of described low voltage start circuit has an initial value.
4. a kind of low voltage start circuit according to claim 1 and 2 is characterized in that, described clock boosting unit comprises: charge pump unit, voltage clamp unit and gate circuit unit;
Described charge pump unit is used for the level amplitude rising with the clock signal of described input, thereby promotes the high level amplitude of described clock signal;
Described voltage clamp unit, be used to detect the charge pump unit output voltage, when described charge pump unit output voltage during greater than the level amplitude of a reference voltage of setting according to the output voltage of input power source voltage or described low voltage start circuit, drive the described clock signal of the shielding input charge pump unit that pulls down switch in the described gate circuit unit, make described charge pump unit stop to boost; When described charge pump output voltage is less than or equal to the level amplitude of described reference voltage, recover the clock signal of the described charge pump unit of input again, described charge pump unit is restarted;
Described gate circuit unit is used for the receive clock signal.
5. a kind of low voltage start circuit according to claim 4, it is characterized in that, the signal that described gate circuit unit receives also comprises the selection signal, this selection signal is the startup of described power supply detecting unit input or the signal of closing described clock boosting unit, described gate circuit unit is selected signal according to this, stops or recovering described charge pump described clock signal is made boosting inverter.
6. a boosting type converter comprises feedback control unit, it is characterized in that also comprising low voltage start circuit;
Described low voltage start circuit comprises:
Oscillator is used to produce the clock signal of the described converting unit of switch;
Converting unit is used for the conversion of input supply voltage to described low voltage start circuit output voltage;
The clock boosting unit is used to promote the voltage amplitude of described oscillator clock signal, to drive described converting unit;
Described feedback control unit is used for the output voltage size according to described boosting type converter, and decision starts or closes described low voltage start circuit, and utilizes the output of described low voltage start circuit to power to the external world.
7. a kind of boosting type converter according to claim 6, it is characterized in that, described low voltage start circuit also comprises: the power supply detecting unit, be used to detect import described oscillator when starting supply voltage whether less than predetermined threshold value, if less than described threshold value then start described clock boosting unit; Otherwise close described clock boosting unit, directly the clock signal with described oscillator output exports described converting unit to.
8. a kind of boosting type converter according to claim 6, it is characterized in that, the power supply of described low voltage start circuit is connected with the output of described input power supply or described low voltage start circuit, and the voltage of the output of described low voltage start circuit has an initial value.
9. according to claim 6 or 7 described a kind of boosting type converters, it is characterized in that described clock boosting unit comprises: charge pump unit, voltage clamp unit and gate circuit unit;
Described charge pump unit is used for the level amplitude rising with the clock signal of described input, thereby promotes the high level amplitude of described clock signal;
Described voltage clamp unit, be used to detect the charge pump unit output voltage, when described charge pump unit output voltage during greater than the level amplitude of a reference voltage of setting according to the output voltage of input power source voltage or described low voltage start circuit, drive the described clock signal of the shielding input charge pump unit that pulls down switch in the described gate circuit unit, make charge pump unit stop to boost; When described charge pump unit output voltage is less than or equal to the level amplitude of described reference voltage, recover the clock signal of the described charge pump unit of input again, described charge pump unit is restarted;
Described gate circuit unit is used for the receive clock signal.
10. a kind of boosting type converter according to claim 9, it is characterized in that, the signal that described gate circuit unit receives also comprises the selection signal, this selection signal is the startup of described power supply detecting unit input or the signal of closing described clock boosting unit, described gate circuit unit is selected signal according to this, stops or recovering described charge pump described clock signal is made boosting inverter.
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| CN 200910088048 CN101938212B (en) | 2009-07-01 | 2009-07-01 | Low-voltage start-up circuit and boost converter |
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| CN 200910088048 CN101938212B (en) | 2009-07-01 | 2009-07-01 | Low-voltage start-up circuit and boost converter |
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| CN101938212B CN101938212B (en) | 2012-12-19 |
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102290983A (en) * | 2011-06-16 | 2011-12-21 | 北京大学 | Charge pump |
| CN102361399A (en) * | 2011-09-28 | 2012-02-22 | 福建华映显示科技有限公司 | Power supply device of thin film transistor liquid crystal display |
| CN103475215A (en) * | 2012-06-06 | 2013-12-25 | 华润矽威科技（上海）有限公司 | Boost structure and its feedback circuit |
| CN104143905A (en) * | 2014-04-21 | 2014-11-12 | 美芯晟科技（北京）有限公司 | Quick start control circuit of converter |
| CN108711918A (en) * | 2018-08-22 | 2018-10-26 | 上海艾为电子技术股份有限公司 | A kind of switched charge circuit |
| CN110932537A (en) * | 2019-12-25 | 2020-03-27 | 启攀微电子（上海）有限公司 | Novel clamping circuit of power supply in wide voltage input sheet |
| CN113691111A (en) * | 2021-10-26 | 2021-11-23 | 上海南麟电子股份有限公司 | Drive circuit and DCDC boost system |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| BE1003675A3 (en) * | 1990-02-23 | 1992-05-19 | Solvay | Stabilized polyamide compositions and shaped objects from same. |
| JP3098471B2 (en) * | 1997-09-22 | 2000-10-16 | 山形日本電気株式会社 | Semiconductor device for low power supply |
| JP4692327B2 (en) * | 2006-02-24 | 2011-06-01 | 株式会社デンソー | Load drive device |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN102290983A (en) * | 2011-06-16 | 2011-12-21 | 北京大学 | Charge pump |
| CN102290983B (en) * | 2011-06-16 | 2014-01-01 | 北京大学 | Charge pump |
| CN102361399A (en) * | 2011-09-28 | 2012-02-22 | 福建华映显示科技有限公司 | Power supply device of thin film transistor liquid crystal display |
| CN102361399B (en) * | 2011-09-28 | 2014-02-26 | 福建华映显示科技有限公司 | Power supply device of thin film transistor liquid crystal display |
| CN103475215A (en) * | 2012-06-06 | 2013-12-25 | 华润矽威科技（上海）有限公司 | Boost structure and its feedback circuit |
| CN103475215B (en) * | 2012-06-06 | 2016-03-30 | 华润矽威科技（上海）有限公司 | Boost configuration and feedback circuit thereof |
| CN104143905A (en) * | 2014-04-21 | 2014-11-12 | 美芯晟科技（北京）有限公司 | Quick start control circuit of converter |
| CN104143905B (en) * | 2014-04-21 | 2017-05-03 | 美芯晟科技（北京）有限公司 | quick start control circuit of converter |
| CN108711918A (en) * | 2018-08-22 | 2018-10-26 | 上海艾为电子技术股份有限公司 | A kind of switched charge circuit |
| CN108711918B (en) * | 2018-08-22 | 2023-12-12 | 上海艾为电子技术股份有限公司 | Switch charging circuit |
| CN110932537A (en) * | 2019-12-25 | 2020-03-27 | 启攀微电子（上海）有限公司 | Novel clamping circuit of power supply in wide voltage input sheet |
| CN113691111A (en) * | 2021-10-26 | 2021-11-23 | 上海南麟电子股份有限公司 | Drive circuit and DCDC boost system |
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