CN103529891A - Soft start device and method - Google Patents

Abstract

The invention discloses a soft start device and method. The soft start device and method are suitable for voltage regulators, especially for non-capacitive voltage regulators. According to the device, a voltage buildup and speed control module is additionally arranged on the basis of an existing voltage regulator circuit and used for controlling the output voltage of an error amplifier, and therefore the output voltage of the voltage regulator circuit can rise to a stable value at a preset speed in the circuit establishment process. According to the corresponding method, the output voltage of the voltage regulator circuit rises to the stable value at the preset speed. Due to the adoption of the scheme, voltage and current impact caused after a power tube is conducted is avoided, and transient current generated in the establishment process of a loop working point is reduced.

Description

A kind of soft starting device and method

Technical field

The present invention relates to a kind of soft Starting Technology, relate in particular to a kind of for voltage regulator (VR:Voltage Regulator) especially without soft start (Soft Start) device and method of capacitance voltage regulator (Cap-less VR).

Background technology

The advantage such as that voltage regulator apparatus has is low in energy consumption, outer member is few, electromagnetic interference (EMI) is little, is applied in SOC (system on a chip) (SOC:system on chip) chip as Power Management Unit.Especially in the portable sets such as mobile phone, individual mobile terminal, the power consumption of SOC chip is required to increasingly stringent, without external capacitive voltage regulator, be widely applied.Shown in Figure 1, the circuit unit of voltage regulator generally includes: a reference source VREF(reference voltage), an error amplifier 12(Error Amplifier), PMOS power tube 13(enhanced power PMOS pipe; Also can adopt enhancement mode NMOS power tube herein, corresponding VFB and VREF need reversal connection), two feedback resistance R1 and R2; Wherein, feedback resistance, error amplifier and PMOS power tube have formed the feedback adjusting loop of VR.During voltage regulator work, reference source module output reference voltage VREF, error amplifier amplifies the difference of VFB and VREF, change the G end signal (output voltage EA_OUT) of PMOS power tube, change its conduction impedance, thereby obtain stable output voltage VO UT(reference voltage VREF under different power supply inputs and load current conditions, play voltage stabilizing reference role).The start-up course of voltage regulator can be divided into 2 parts, power up (power supply rises to the process of establishing of stationary value from no-voltage) respectively:<1>,, now internal node voltages is indefinite, power tube conducting is also charged to load capacitance, power on electric current size and power supply is set up speed and magnitude of voltage is closely related, speed is faster, and voltage is higher, and VOUT overshoot and charged electrical fail to be convened for lack of a quorum larger.<2>, the process of establishing of loop working point.Adjustment loop is feedback voltage and the reference voltage of VOUT relatively, sets up working point.The speed of setting up of the value of quiescent point, load capacitance size and VOUT all may cause larger current over pulse.Shown in Fig. 1, RL represents pull-up resistor, and CL is load capacitance, and the surge current when CL is larger in start-up course is more remarkable; Hour, in start-up course, overshoot voltage is more remarkable for CL.

Soft Starting Technology, for eliminating overshoot voltage (Overshoot Voltage) and the surge current (Inrush Current) of voltage regulator start-up course.But, existing soft Starting Technology has run into difficulty in following background: the system power-on time of (1) PnP device (Time Created of chip power) reaches 10nS rank, when prior art is unable to cope with fast powering-up, the VR especially overshoot voltage of Cap-less VR impacts, and damage utilizes the circuit of VR power supply; (2) when extremely fast powering on, VR may exist larger immediate current to impact, and causes power tube to enter breech lock (La t ch Up) state, the circuit of damage VR own.(3) in some portable equipment, SOC chip is provided with to restrictive supply standard, comprise instantaneous power requirement, this has become one of the entry criteria in market.If the moment surge current to VR is not controlled, may cause SOC chip to work.

Summary of the invention

The main technical problem to be solved in the present invention is, a kind of soft starting device and method are provided, and it can, in the moment of device power, eliminate voltge surge.

For solving the problems of the technologies described above, the invention provides a kind of soft starting device, comprise voltage modulator circuit and Voltage Establishment rate control module, in described voltage modulator circuit, be provided with and connect the power tube of power access end and for regulating the error amplifier of described power tube conducting resistance; Described Voltage Establishment rate control module, for controlling the output voltage of described error amplifier, makes the output voltage of described voltage modulator circuit by set rate, rise to stationary value when circuit is set up.

During enforcement, also can comprise the current control module that powers on, described in the current control module that powers on for detection of power access end, whether there is power supply input, control the conducting after the schedule time of described power tube when thering is power supply input at described power access end.

, comprise voltage modulator circuit, in described voltage modulator circuit, be provided with and connect the power tube of power access end and for regulating the error amplifier of described power tube conducting resistance; Also comprise power on current control module and the Voltage Establishment rate control module that is connected described error amplifier; Whether the described current control module that powers on has external power source input for detection of power access end, controls described power tube conducting after the schedule time (setting up circuit) when having external power source input at described power access end; Described Voltage Establishment rate control module is for controlling the output voltage of described error amplifier, and with after described power tube conducting, the output voltage of controlling described voltage modulator circuit rises to stationary value by set rate.

A kind of soft-start method, for voltage modulator circuit, in described voltage modulator circuit, be provided with for accessing the power tube of power access end and for regulating the error amplifier of described power tube conducting resistance, also comprising Voltage Establishment rate control module, the method step is:

Described Voltage Establishment rate control module is controlled the output voltage of described error amplifier;

When circuit is set up, described Voltage Establishment rate control module is by described output voltage, and the output voltage of controlling described voltage modulator circuit rises to stationary value by set rate.

During enforcement, also comprise the current control module that powers in described voltage modulator circuit, the method also comprises step:

The described current control module that powers on detects power access end;

There is power supply when input described power access end being detected, described in the current control module that powers on control the conducting after the schedule time of described power tube, realize circuit and set up.

The invention has the beneficial effects as follows: a kind of soft starting device and method, this device by setting up Voltage Establishment rate control module on the basis of existing voltage modulator circuit, for controlling the output voltage of described error amplifier, make the output voltage of voltage modulator circuit by set rate, rise to stationary value when circuit is set up; Corresponding method rises to stationary value by the output voltage of voltage modulator circuit by set rate; This scheme has avoided the voltage and current after power tube conducting to impact, and reduces the transient current in the process of establishing of loop working point.

Further, this device comprises the current control module that powers on, whether the current control module that powers on has power supply input for detection of power access end, and when having power supply input, power tube conducting after the schedule time of controlling voltage regulator accesses described power access end; Corresponding method has power supply when input described power access end being detected, controls the conducting after the schedule time of described power tube; This device and method detect power access end to power tube conducting access power supply eliminated during this period of time fast powering-up time voltage overshoot and surge current, protected circuit.

Accompanying drawing explanation

Fig. 1 is existing voltage modulator circuit schematic diagram;

Fig. 2 A is the principle schematic of an embodiment of the present invention;

Fig. 2 B is the schematic diagram that Fig. 2 A illustrated embodiment is applied to voltage regulator shown in Fig. 1;

Fig. 3 A is further circuit theory schematic diagram of Fig. 2 A embodiment;

Fig. 3 B is the schematic diagram that Fig. 3 A illustrated embodiment is applied to voltage regulator shown in Fig. 1;

Fig. 4 is the circuit diagram of current control module of powering in previous embodiment;

Fig. 5 is the circuit diagram of Voltage Establishment rate control module in previous embodiment;

Fig. 6 is the simulation waveform figure that powers on of the voltage regulator chip realized of the present invention.

Embodiment

Below by embodiment, by reference to the accompanying drawings the present invention is described in further detail.

As shown in Figure 2 A, a kind of soft starting device, comprise voltage modulator circuit 14 and Voltage Establishment rate control module 11, in described voltage modulator circuit 14, be provided with and connect the power tube 13 of power access end and for regulating the error amplifier 12 of described power tube 13 conducting resistance; Described Voltage Establishment rate control module 11, for controlling the output voltage EA_OUT of described error amplifier 12, makes the output voltage VO UT of described voltage modulator circuit 14 by set rate, rise to stationary value when circuit is set up.This circuit works after the current control circuit that powers on, for reducing the transient current of loop working point process of establishing.

Described stationary value, refers to that error amplifier 12 is independent of 11 pairs of power tubes 13 of Voltage Establishment rate control module and controls produced output voltage VO UT.

When circuit is set up, refer to the moment that starts output voltage VO UT at voltage modulator circuit 14, the process that rises to stationary value by set rate is the continuity backward of this time point.

During enforcement, the output voltage VO UT of voltage modulator circuit 14 presses set rate and rises, and can control by Voltage Establishment rate control module 11 the output voltage EA_OUT of described error amplifier 12, thereby the mode of the resistance of change power tube 13 realizes.

Shown in Fig. 3 A, 5, during enforcement, described Voltage Establishment rate control module 11 comprises the tenth PMOS pipe 111(M10) and be connected to the tenth PMOS and manage the rising voltage source 112 on 111 grids, the voltage SS_CTRL that set rate rises is pressed in described rising voltage source 112 outputs, the conducting resistance of controlling described the tenth PMOS pipe 111 rises in described set rate by geometric ratio, until the tenth PMOS pipe 111 blocking-up.

When implementing, rising voltage source 112 can just start output voltage when power access end VIN has power supply input, also can At All Other Times, for example, at power tube 13, open output voltage afterwards.Corresponding, if rising voltage source 112 starts output voltage when power access end VIN has power supply input, 112 of rising voltage sources also can be used for detecting power access end VIN, and there is power supply when input described power access end VIN being detected, control described rising voltage source 112 output voltages.Corresponding, if rising voltage source 112 output voltage after power tube 13 is opened, 112 of rising voltage sources also can be used for detection power pipe 13 on off states.

During enforcement, described error amplifier 12 comprises the differential pair tube 121 consisting of two metal-oxide-semiconductors, and two grids of differential pair tube 121 are external reference source VREF(reference voltage respectively) and voltage feedback signal VFB; The source electrode of described the tenth PMOS pipe 111 and drain electrode be corresponding to be connected on the source electrode and drain electrode of a metal-oxide-semiconductor of differential pair tube 121 external reference source VREF.

Described rising voltage source 112 comprises the second mirror image circuit 1121 and the 3rd capacitor C 3; Described the second mirror image circuit 1121 external power supply incoming end VIN and bias current IB_SS, and the second image current I2 exporting corresponding to this bias current IB_SS to described the 3rd capacitor C 3, the 3rd capacitor C 3 another extremely external ground wire VSS; Described the 3rd capacitor C 3 is the output terminal of the described voltage source 112 rising by set rate with the link of described the second mirror image circuit 1121.

Embodiment as shown in Figure 5, differential pair tube 121 consists of the 11 PMOS pipe M11 and the 12 PMOS pipe M12, and the external reference source VREF of grid of the 11 PMOS pipe M11, source electrode are connected with the source electrode of the tenth PMOS pipe 111, draining is connected with the drain electrode of the 11 PMOS pipe M11 the tenth PMOS pipe 111; The breadth length ratio of described the tenth PMOS pipe 111 in described Voltage Establishment rate control module 11 is greater than the breadth length ratio of described the 11 PMOS pipe M11 and the 12 PMOS pipe M12.Wherein, breadth length ratio difference is larger, and effect is more obvious.

Concrete, as shown in Fig. 1,2B, 3B, between the output terminal electrode of described voltage modulator circuit 14, be also provided with two feedback resistance R1, R2 of serial connection.Described feedback resistance, power tube 13 and error amplifier 12 form VR feedback adjusting loop, and described voltage feedback signal VFB i.e. the negative feedback input signal of this VR adjustment loop (voltage feedback signal VFB is R1 and the dividing potential drop of R2 to VOUT).Its signal stream is: error amplifier 12 output voltage EA_OUT are passed to the grid of power tube 13, thereby change the output end voltage VOUT of voltage modulator circuit 14, between two feedback resistance R1, R2, the magnitude of voltage of tie point is inputted described error amplifier 12 as negative feedback input signal, thus the output voltage of regulating error amplifier 12.

During enforcement, this soft starting device also comprises that set rate arranges module, for the schedule time according to described conducting power tube 13 (with reference to below setting up the scheme part of the current control module 10 that powers on), the size of described the second image current I 2 and the size of the 3rd capacitor C 3 are set, thereby change the size of described set rate.

More specifically, in conjunction with Fig. 5, the principle of work of Voltage Establishment rate control module 11 is that the voltage SS_CTRL and the reference source VREF that utilize a road to rise by set rate control output voltage simultaneously.Be characterized in that both do not exist the handoff procedure of switching regulator.The output voltage VO UT that the voltage SS_CTRL rising by set rate in start-up course controls voltage modulator circuit 14 slowly sets up, and this mainly relies on the tenth PMOS pipe the 111 and the 11 PMOS pipe size difference of M11 and the negative feedback voltage VFB of VR adjustment loop to be used for realizing.

During enforcement, concrete, the breadth length ratio of described the tenth PMOS pipe 111 is greater than the breadth length ratio of described the 11 PMOS pipe M11 and the 12 PMOS pipe M12, in start-up course, the tenth PMOS that flows through manages 111 electric currents much larger than the electric current of the 11 PMOS pipe M11, and the tenth PMOS pipe the 111 and the 12 PMOS pipe M12 forms substantial difference input to pipe; The current capacity of the tenth PMOS pipe 111 is greater than the 12 PMOS pipe M12, and system exists input imbalance Vos(due to negative feedback, and the dividing potential drop VFB of output voltage VO UT equates with SS_CTRL-Vos), in start-up course, there is formula:

$V_{\mathrm{OUT}}=(1+\frac{R1}{R2})V_{\mathrm{FB}}=(1+\frac{R1}{R2})(V_{\mathrm{SS}\_\mathrm{CTRL}}-V_{\mathrm{OS}})$

Vos is the system input offset voltage of error amplifier, when the breadth length ratio of the tenth PMOS pipe 111 is greater than the 12 PMOS pipe M12, Vos be on the occasion of.

Concrete, charging current (the second image current I2), to the 3rd capacitor C 3 chargings, is pressed the voltage SS_CTRL rising that set rate rises, and output voltage VO UT equal proportion rises.Therefore, change the size of the second image current I2 and the 3rd capacitor C 3, can realize the accurate control that output voltage VO UT sets up speed.

The voltage SS_CTRL rising along with set rate further rises, and the electric current that flows through the tenth PMOS pipe 111 is slowly reduced to zero, and the tenth PMOS pipe 111 breaks from loop, and error amplifier recovers normal operating conditions, and output voltage VO UT is stabilized in to setting value.The source voltage terminal of the time that error amplifier is switched to normal operating conditions by the second image current I2, the 3rd capacitor C 3 and the tenth PMOS pipe 111 determines jointly, irrelevant with the size of output voltage VO UT.The output voltage VO UT expression formula of steady state (SS):

$V_{\mathrm{OUT}}=(1+\frac{R1}{R2})V_{\mathrm{FB}}=(1+\frac{R1}{R2})V_{\mathrm{REF}}$

During enforcement, in the domain of integrated circuit, differential pair tube the 11 PMOS pipe M11, the 12 PMOS pipe M12 need be dummy to guarantee good coupling, and the tenth 111 of PMOS pipes can utilize dummy pipe to realize, and reduce extra chip area consumption.

During enforcement, can utilize the top crown voltage (as Fig. 4) of the second capacitor C 2 in current control module 10 that powers on as control signal, as the second image current I2(as Fig. 5) current switch; When bias current IB_SS reaches after a period of time the second capacitor C 2 chargings, just allow the second image current I2 electric current to start charging.

During enforcement, can add a circuit, regulate the time of power on current control module 10 and 11 two module works of Voltage Establishment rate control module.

With reference to a kind of soft starting device shown in Fig. 1,2A, also can comprise the current control module 10 that powers on.Whether the current control module that powers on 10 has power supply input for detection of power access end VIN, and when power supply input being detected, first power tube 13 is closed, then after the schedule time, open again conducting power tube 13 and make voltage modulator circuit 14 access power supplys (input power of power ratio control pipe 13 conducting access power access end VIN after the schedule time).After power tube 13 conductings (circuit foundation), aforesaid Voltage Establishment rate control module 11 just starts performance and controls the effect that the output voltage VO UT of voltage modulator circuit 14 rises.

During enforcement, shown in Fig. 3 A, 3B, described power tube 13 is metal-oxide-semiconductor, described in the current control module 10 that powers on comprise switch element 102 and control module 101; Described switch element 102 is connected between described power access end VIN and the grid of described power tube 13; Described control module 101 connects described power access end and described switch element 102, controlling described switch element 102 has the described schedule time conducting after power supply input or closes at described power access end, make grid and described power access end VIN conducting or the disconnection of described power tube 13, thereby realize the conducting of described power tube 13.

During enforcement, as shown in Fig. 2 B, 3B, Fig. 4, described power tube 13 is all PMOS pipe or NMOS pipe with switch element 102; The source electrode of described switch element and drain electrode are connected between described power access end VIN and the grid of described power tube 13, realize the switch of the grid of power access end VIN and power tube 13 and control.

Fig. 3 B, embodiment illustrated in fig. 4 in, power tube 13 and switch element 102 (PMOS pipe M1) are PMOS pipe.

As described in Figure 4, control module 101 is controlled and is comprised the first mirror image circuit 1011, the first capacitor C 1, the second capacitor C 2 and impact damper 1012; One end of described the first capacitor C 1, the second capacitor C 2 all connects ground wire VSS, and the other end of described the first capacitor C 1 accesses the grid of described switch element 102, and the other end of described the second capacitor C 2 connects the output terminal of described the first mirror image circuit 1011; Described the first mirror image circuit 1011 external power supply incoming end VIN and bias current IB_SS be the first mirror image current Ic corresponding to this bias current IB_SS to described the second capacitor C 2 outputs; Described impact damper 1012 is connected to described power access end VIN and ground wire VSS, and for described the first mirror image circuit 1011 and described the second capacitor C 2 junction signals being converted to the grid that is passed to described switch element 102 after digital signal.

During enforcement, this soft starting device also can comprise that the schedule time arranges module; Described impact damper 1012 forms (embodiment as shown in the figure by least two phase inverters, comprise the first phase inverter 10121 and the second phase inverter), the first phase inverter 10121 being wherein directly connected with described the second capacitor C 2 includes the 4th PMOS pipe M4 and the 5th NMOS pipe M5; The described schedule time module is set for the size of described first mirror image current Ic is set, the threshold voltage (realizing the voltage of blocking) of the threshold voltage (realizing the voltage of conducting) of the size of the second capacitor C 2, the 4th PMOS pipe M4 and the 5th NMOS pipe M5 one or more, thereby change the described schedule time.

More specifically, the principle of work of the current control module that powers on 10, shown in 2B, 4, switch element 102(M1) grid terminal voltage is given by the first capacitor C 1, thereby eliminated the not stationary state in power up, guarantee switch element 102 conductings and the output voltage EA_OUT of error amplifier 12 is drawn high to the input voltage of power access end VIN, close power tube 13.Base modules is started working subsequently, bias current IB_SS produces, first mirror image current Ic is to the second capacitor C 2 chargings, the second capacitor C 2 top crown voltages progressively rise, and final plant closure switch element 102, the output voltage EA_OUT that discharges error amplifier 12, the feedback adjusting loop of VR enters the process of establishing of quiescent point.The size of the second capacitor C 2, first mirror image current IC, the 4th PMOS pipe M4, the 5th NMOS pipe M5 (referring to respectively the size of first mirror image current I c, the cut-in voltage of the size of the second capacitor C 2, the 4th PMOS pipe M4 and the cut-in voltage of the 5th NMOS pipe M5) has determined the release time (schedule time) of power tube jointly.Computing formula is as follows:

T_Release=VM*C2/Ic

Wherein VM is the mid point level that M4 and M5 form phase inverter.

$\mathrm{VM}=\frac{\mathrm{VIN}-\left|\mathrm{VTp}\right|+\sqrt{\frac{\mathrm{\&beta;n}}{\mathrm{\&beta;p}}}*\mathrm{TVn}}{1+\sqrt{\frac{\mathrm{\&beta;n}}{\mathrm{\&beta;p}}}},$

VTp, VTn is respectively the threshold voltage of M4 and M5; β p, β n is and M4, the size Physics amount of M5.

During enforcement, as Fig. 5 impact damper forms (four metal-oxide-semiconductor M4, M5, M6, M7 form) formation by least two phase inverters, it can prevent switch element 102 abnormals after power tube discharges.When significantly the changing fast in normal range of the power supply input of power access end VIN, due to the 6th PMOS pipe M6 conducting, the power supply input that the first capacitor C 1 top crown is followed power access end VIN changes, thereby guarantees that switch element 102 ends all the time.

The input power that the current control circuit that powers on is applied to power access end VIN, from the process of establishing that is raised to stationary value above freezing, is closed the power tube of voltage regulator; Being characterized in controlling effect does not need to detect output voltage VO UT, and the response time is extremely short, thereby can be applicable to the extremely fast process of establishing of other power access end of 10ns level VIN.

When implementing, Voltage Establishment rate control module 11 suitable release time is by the ascending velocity of the comprehensive voltage SS_CTRL that press set rate rising when weighing power tube 13 and discharging, also will be by comprehensive release time (release time that the current control circuit that powers on determines) and the VR(voltage modulator circuit of weighing power tube 13) load capacitance CL size set, to limit the surge current peak value of moment.

A kind of soft starting device embodiment as described in Fig. 2-6, the Current Control that simultaneously powers on and Voltage Establishment speed are controlled.Specifically comprise voltage modulator circuit 14, in voltage modulator circuit 14, be provided with and connect the power tube 13 of power access end and for regulating the error amplifier 12 of described power tube 13 conducting resistance; Also comprise power on current control module 10 and the Voltage Establishment rate control module 11 that is connected described error amplifier 12; Whether the described current control module 10 that powers on has external power source input for detection of power access end, controls the conducting after the schedule time of described power tube 13 when having external power source input at described power access end; Described Voltage Establishment rate control module 11 is for controlling the output voltage of described error amplifier 12, and with after described power tube 13 conductings, the output voltage of controlling described voltage modulator circuit 14 rises to stationary value by set rate.

With reference to aforementioned means, a kind of soft-start method, for voltage modulator circuit, in described voltage modulator circuit 14, be provided with for accessing the power tube 13 of power access end VIN and for regulating the error amplifier 12 of described power tube 13 conducting resistance, also comprise Voltage Establishment rate control module 11, the method step is: the output voltage EA_OUT of 11 pairs of described error amplifiers 12 of described Voltage Establishment rate control module controls; When circuit is set up (power tube conducting or say power tube turn-on power), described Voltage Establishment rate control module 11 is by the output voltage of described error amplifier 12, and the output voltage VO UT that controls described voltage modulator circuit 14 rises to stationary value by set rate when circuit is set up.

During enforcement, described error amplifier 12 comprises the differential pair tube 121 consisting of two metal-oxide-semiconductors, and two grids of differential pair tube 121 are external reference source VREF and voltage feedback signal VFB respectively; The step of the output voltage EA_OUT of the described error amplifier 12 of described control is: when described power access end has power supply input, a voltage SS_CTRL who rises by set rate of place in circuit is set; When circuit is set up, (can refer to hereinafter described after power tube 13 conductings) should press the alternative described reference source VREF of voltage SS_CTRL that set rate rises; After described output voltage VO UT rises to stationary value, described in cutting off, press the access of the voltage SS_CTRL of set rate rising, recover the voltage stabilizing reference role of reference source VREF.

During enforcement, described access of pressing the voltage SS_CTRL of set rate rising is managed realization with cut-out by a PMOS.

Concrete, should press in the voltage SS_CTRL uphill process of set rate rising, have the magnitude of voltage higher than the threshold voltage of controlled PMOS pipe, according to set rate, rise to after this magnitude of voltage, the PMOS controlling closes, and error amplifier 12 recovers original control procedure.

During enforcement, in described voltage modulator circuit 14, also comprise the current control module 10 that powers on, this soft-start method also can comprise step: described in power on current control module 10 detect power access end VIN; In power supply when input that described power access end VIN detected, described in the current control module 10 that powers on control the conductings after the schedule time of described power tube 13 and access described power access end VIN, realize described circuit and set up.

During enforcement, by controlling, described power access end signal is converted to switching signal, and export the mode of this signal intensity to described power tube 13 in the schedule time, realizes described power tube 13 and change conducting state into by closed condition.

During enforcement, the described schedule time, by the electric capacity of constant-current charge, the time that its voltage rises to predetermined value defines (referring to aforementioned computing formula).

During enforcement, Voltage Establishment rate control module 11 suitable release time is by the comprehensive ascending velocity of press the voltage SS_CTRL that set rate rises when weighing power tube 13 and discharging, also will be by release time (release time of the current control circuit that powers on decision) and the VR(voltage modulator circuit of comprehensive measurement power tube 13) load capacitance CL size set.Guarantee at least reference voltage lower than reference source VREF in 13 conducting moments of power tube of the voltage SS_CTRL that rises by set rate, to reduce power tube On current now.

During enforcement, the inventive method can be expanded with reference to aforesaid device.

The simulation waveform that powers on of the voltage regulator chip of realizing based on the present invention as shown in Figure 6, signature waveform based on VR of the present invention when plug powers on, output voltage VO UT remains zero (power tube is closed) in a period of time after powering on, the input current peak value of power supply is less than 3mA, after power tube discharges, effect due to feedback, the electric resistance partial pressure of output voltage VO UT i.e. (voltage feedback signal VFB) is being followed the voltage SS_CTRL signal rising of rising by set rate, and always has the difference of input imbalance VOS; Thereby guarantee that output voltage VO UT slowly sets up under the control of voltage SS_CTRL signal of pressing set rate rising, current peak is also controlled as being about 13mA, is well controlled.

During enforcement, apparatus of the present invention and method are applicable to utilize NMOS as the voltage regulator structure of power tube; Be applicable to linear model charge pump circuit or the non-loaded convert of capacitor to voltage circuit of regulating power pipe.

Apparatus of the present invention and method tool have the following advantages:<1>, the present invention can eliminate voltage overshoot and surge current phenomenon simultaneously, realizes the mild foundation of output voltage, limiting input current peak value.<2>, the present invention is particularly useful for the situation of the voltage regulator (Capless VR) without external load capacitance.<3>, the present invention is applicable to the start-up course under the various speed that powers on, electrifying startup process especially extremely fast.<4>, the present invention is simple in structure, multiplexing as far as possible VR(voltage modulator circuit) circuit component, in adjustment loop, do not increase impedance and capacitive reactance, kept the response speed of VR.<5>, in the present invention, the speed of setting up of soft start-up process and reference voltage (reference source VREF) is irrelevant.<6>, the present invention output voltage VO UT of not needing to detect voltage modulator circuit 14 realizes the switching of soft start state and the state of adjustment of voltage regulator, soft starting circuit the time point of setting automatically with the disconnection of VR adjustment loop.

Above content is in conjunction with concrete embodiment further description made for the present invention, can not assert that specific embodiment of the invention is confined to these explanations.For general technical staff of the technical field of the invention, without departing from the inventive concept of the premise, can also make some simple deduction or replace, all should be considered as belonging to protection scope of the present invention.

Claims (17)

1. a soft starting device, it is characterized in that, comprise voltage modulator circuit (14) and Voltage Establishment rate control module (11), in described voltage modulator circuit (14), be provided with and connect the power tube (13) of power access end and for regulating the error amplifier (12) of described power tube (13) conducting resistance; Described Voltage Establishment rate control module (11), for controlling the output voltage of described error amplifier (12), makes the output voltage of voltage modulator circuit (14) by set rate, rise to stationary value when circuit is set up.

2. soft starting device as claimed in claim 1, it is characterized in that, described Voltage Establishment rate control module (11) comprises the tenth PMOS pipe (111) and is connected to the rising voltage source (112) on the tenth PMOS pipe (111) grid, the voltage that set rate rises is pressed in described rising voltage source (112) output, the conducting resistance geometric ratio of controlling described the tenth PMOS pipe (111) rises in described set rate, until described the tenth PMOS pipe (111) blocking-up.

3. soft starting device as claimed in claim 2, is characterized in that, described error amplifier (12) comprises the differential pair tube (121) consisting of two metal-oxide-semiconductors, and two grids of differential pair tube (121) are external reference source and voltage feedback signal respectively; Described the tenth PMOS manages on the source electrode of (111) and the source electrode and drain electrode of the metal-oxide-semiconductor that drain electrode correspondence is connected to the external reference source of differential pair tube (121).

4. soft starting device as claimed in claim 3, is characterized in that, described rising voltage source (112) comprises the second mirror image circuit (1121) and the 3rd electric capacity; The link of described the 3rd electric capacity and described the second mirror image circuit (1121) is the output terminal of the described voltage source (112) rising by set rate; Described the second mirror image circuit (1121) external power supply incoming end and bias current, and export the second image current corresponding to this bias current, another extremely external ground wire of the 3rd electric capacity to described the 3rd electric capacity.

5. soft starting device as claimed in claim 4, it is characterized in that, described differential pair tube (121) consists of the 11 PMOS pipe and the 12 PMOS pipe, and the external reference source of grid of described the 11 PMOS pipe, source electrode are connected with the source electrode that the tenth PMOS manages (111), draining is connected with the drain electrode of the 11 PMOS pipe the tenth PMOS pipe (111); The breadth length ratio of described the tenth PMOS pipe (111) in described Voltage Establishment rate control module (11) is greater than the breadth length ratio of described the 11 PMOS pipe and the 12 PMOS pipe.

6. soft starting device as claimed in claim 5, is characterized in that, is also provided with two feedback resistances of serial connection between the output terminal of described voltage modulator circuit (14); Described error amplifier (12) output voltage is to power tube (13) grid, thus the output end voltage of change voltage modulator circuit (14), and the magnitude of voltage between two feedback resistances is inputted described error amplifier (12) as negative feedback input signal.

7. the soft starting device as described in claim 1 to 6 any one, it is characterized in that, this soft starting device also comprises the current control module that powers on (10), whether the described current control module that powers on (10) has power supply input for detection of power access end, controls described power tube (13) conducting after the schedule time when having power supply input at described power access end.

8. soft starting device as claimed in claim 7, it is characterized in that, this soft starting device also comprises that set rate arranges module, for the schedule time according to described conducting power tube (13), the size of described the second image current and the size of the 3rd electric capacity are set, thereby change the size of described set rate.

9. soft starting device as claimed in claim 7, is characterized in that, described power tube (13) is metal-oxide-semiconductor, described in the current control module (10) that powers on comprise switch element (102) and control module (101); Described switch element (102) is connected between described power access end and the grid of described power tube (13); Described control module (101) connects described power access end and described switch element (102), controlling described switch element (102) has the described schedule time conducting after power supply input or closes at described power access end, make grid and described power access end conducting or the disconnection of described power tube (13), thereby realize the conducting of described power tube (13).

10. soft starting device as claimed in claim 9, is characterized in that, described power tube (13) is all PMOS pipe or NMOS pipe with switch element (102); The source electrode of described switch element and drain electrode are connected between described power access end and the grid of described power tube (13).

11. soft starting devices as claimed in claim 10, is characterized in that, described control module (101) comprises the first mirror image circuit (1011), the first electric capacity, the second electric capacity and impact damper (1012); One end of described the first electric capacity, the second electric capacity all connects ground wire, and the other end of described the first electric capacity accesses the grid of described switch element (102), and the other end of described the second electric capacity connects the output terminal of described the first mirror image circuit (1011); Described the first mirror image circuit (1011) external power supply incoming end and bias current be the first mirror image current corresponding to this bias current to described the second electric capacity output; Described impact damper (1012) is connected to described power access end and ground wire, and for described the first mirror image circuit (1011) and described the second electric capacity junction signal being converted to the grid that is passed to described switch element (102) after digital signal.

12. soft starting devices as claimed in claim 11, is characterized in that, this soft starting device also comprises that the schedule time arranges module; Described impact damper (1012) comprises the first phase inverter (10121) and the second phase inverter, and described the first phase inverter (10121) is connected with described the second electric capacity, and it comprises the 4th PMOS pipe and the 5th NMOS pipe; The described schedule time module is set for the size of described first mirror image current is set, the cut-in voltage of the size of the second electric capacity, the 4th PMOS pipe and the cut-in voltage of the 5th NMOS pipe one or more.

13. 1 kinds of soft-start methods, for voltage modulator circuit (14), in described voltage modulator circuit (14), be provided with power tube (13) for accessing power access end and for regulating the error amplifier (12) of described power tube (13) conducting resistance, it is characterized in that, also comprise Voltage Establishment rate control module (11), the method step is:

Described Voltage Establishment rate control module (11) is controlled the output voltage of described error amplifier (12);

When circuit is set up, described Voltage Establishment rate control module (11) is by described output voltage, and the output voltage of controlling described voltage modulator circuit (14) rises to stationary value by set rate.

14. soft-start methods as claimed in claim 13, is characterized in that, described error amplifier (12) comprises the differential pair tube (121) consisting of two metal-oxide-semiconductors, and two grids of differential pair tube (121) are external reference source and voltage feedback signal respectively; The step of the output voltage of the described error amplifier of described control (12) is: when described power access end has power supply input, the voltage rising by set rate of place in circuit is set; When circuit is set up, should press the alternative described reference source of voltage that set rate rises; After described output voltage rises to stationary value, described in cutting off, press the access of the voltage of set rate rising, recover the voltage stabilizing reference role of reference source.

15. soft-start methods as described in claim 13 or 14, is characterized in that, in described voltage modulator circuit (14), also comprise the current control module that powers on (10), the method also comprises step:

The described current control module that powers on (10) detects power access end;

There is power supply when input described power access end being detected, described in the current control module (10) that powers on control described power tube (13) conducting after the schedule time, realize circuit and set up.

16. soft-start methods as claimed in claim 15, it is characterized in that, by controlling, described power access end signal is converted to switching signal, and in schedule time output signal, be changed to described power tube (13) mode, realize described power tube (13) and change conducting state into by closed condition; The described schedule time is the time that its voltage of electric capacity of a constant-current charge rises to predetermined value.

17. 1 kinds of soft starting devices, it is characterized in that, comprise voltage modulator circuit (14), in described voltage modulator circuit (14), be provided with and connect the power tube (13) of power access end and for regulating the error amplifier (12) of described power tube (13) conducting resistance; Also comprise the current control module that powers on (10) and the Voltage Establishment rate control module (11) that is connected described error amplifier (12); Whether the described current control module that powers on (10) has external power source input for detection of power access end, controls described power tube (13) conducting after the schedule time when having external power source input at described power access end; Described Voltage Establishment rate control module (11) is for controlling the output voltage of described error amplifier (12), and with after described power tube (13) conducting, the output voltage of controlling described voltage modulator circuit (14) rises to stationary value by set rate.

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