Background technology
In the design of many integrated circuits, cause circuit to damage for the inrush current (InrushCurrent) that prevents the initial stage of activating is excessive, be provided with soft starting circuit usually in order to a soft-start signal to be provided, in order to the restriction inrush current.
Fig. 1 (A) shows the circuit diagram of the integrated circuit (IC) chip 10A that is provided with existing soft starting circuit 12.Integrated circuit (IC) chip 10A has a main circuit 11 and a soft starting circuit 12.Main circuit 11 is in order to carry out the designed circuit function that realizes of integrated circuit (IC) chip 10A (representing as summarizing with output signal OUT) in Fig. 1 (A).For example, the function of being estimated as integrated circuit (IC) chip 10A is used for when supply of current under the voltage that overregulates is given load, and main circuit 11 is implemented by voltage regulators miscellaneous such as changeover voltage adjuster or charge pump voltage adjusters.Soft starting circuit 12 is in order to provide a soft-start signal V
STo main circuit 11, in order to the restriction inrush current.Usually, soft-start signal V
SIt is a voltage signal that rises gradually.Shown in Fig. 1 (A), soft starting circuit 12 has a soft start current source I
SWith a soft start capacitor C
SSoft start current source I
STo soft start capacitor C
SCharging makes across soft start capacitor C
SThe potential difference V at two ends
SRise gradually, in order to as soft-start signal V
SSince the factor of size, soft start capacitor C
SUsually be arranged at the outside of integrated circuit (IC) chip 10A, via electrical pin (Pin) P
SAnd be connected in soft start current source I
S
Fig. 1 (B) shows the circuit diagram of a plurality of passage integrated circuit (IC) chip 10B.A plurality of passage integrated circuit (IC) chip 10B have main circuit passage 11-1,11-2 that n can independently control, to 11-n, wherein n is the integer more than or equal to 2.Cause circuit to damage for the inrush current that prevents the initial stage of activating is excessive, each main circuit passage 11-1,11-2, to 11-n all be provided with a soft starting circuit 12-1,12-2 accordingly, to 12-n, in order to a soft-start signal V to be provided
S1, V
S2, to V
SnOwing to each soft starting circuit 12-1,12-2, all have an outside soft start capacitor C to 12-n
S1, C
S2, to C
Sn, make it respectively via soft start current source I
S1, I
S2, to I
SnCharge and generation soft-start signal V
S1, V
S2, to V
SnSo a plurality of passage integrated circuit (IC) chip 10B must be provided with the electrical pin P of corresponding number
S1, P
S2, to P
Sn, in order to connect outside soft start capacitor C respectively
S1, C
S2, to C
SnThis will cause the oversize and electrical too much shortcoming of pin of Chip Packaging.Moreover, outside soft start capacitor C
S1, C
S1, to C
SnNumber also cause the huge and bed hedgehopping manufacturing cost of external circuit size too much.
Description of drawings
Fig. 1 (A) has shown existing circuit diagram with single passage integrated circuit (IC) chip of soft start function;
Fig. 1 (B) has shown the circuit diagram of a plurality of passage integrated circuit (IC) chip with soft start function that have earlier;
Fig. 2 has shown the circuit diagram according to the soft starting circuit in regular turn of a plurality of circuit paths of the present invention;
Fig. 3 has shown the flow chart according to the soft-start method in regular turn of a plurality of circuit paths of the present invention; And
Fig. 4 has shown the circuit diagram according to an example of sequencing circuit of the present invention.
The primary clustering symbol description
Many passage integrated circuit (IC) chip of the single passage integrated circuit (IC) chip of 10A 10B
11 main circuits 11-1~11-n main circuit passage
12,12-1~12-n soft starting circuit
20 a plurality of passage integrated circuit (IC) chip of the present invention
21-1~21-n main circuit passage 22 is soft starting circuit in regular turn
23 sequencing circuits 24 circuit of energizing
25 charging/discharging control circuits, 26 charge switch circuit
26-1~26-n switch element 27 discharge switching circuits
C
S, C
S1~C
SnSoft start capacitor I
S, I
S1~I
SnThe soft start current source
P
S, P
S1~P
SnElectrical pin EN1~ENn enabling signal
OUT1~OUTn output signal RDY gets signal ready
SC, SC1~SCn charging signals SD discharge signal
V
Fb1~V
FbnFeedback signal V
Ref1~V
RefnReference signal
V
S, V
S1~V
SnSoft-start signal
Embodiment
Explanation hereinafter and accompanying drawing will be stated and other purpose, feature, more obvious with advantage before will making the present invention.Now describe in detail according to preferred embodiment of the present invention with reference to the accompanying drawings.
Fig. 2 has shown the circuit diagram according to the soft starting circuit in regular turn 22 of a plurality of circuit paths of the present invention.As shown in the figure, a plurality of passage integrated circuit (IC) chip 20 have main circuit passage 21-1,21-2 that n can independently control, to 21-n, and wherein n is the integer more than or equal to 2.Cause circuit to damage for the inrush current that prevents the initial stage of activating is excessive, produce soft-start signal V singly according to a predetermined order according to soft starting circuit in regular turn 22 of the present invention
S1, V
S2, to V
Sn, and put on main circuit passage 21-1,21-2 respectively, to 21-n.Soft starting circuit 22 is by n soft start current source I in regular turn
S1, I
S2, to I
Sn, a sequencing circuit 23 and a soft start capacitor C
SConstitute.On the one hand, soft start current source I
S1, I
S2, to I
SnAll be connected in sequencing circuit 23; On the other hand, soft start capacitor C
SVia an electrical pin P
SBe connected in sequencing circuit 23.Sequencing circuit 23 is according to predetermined sequential control soft start current source I
S1, I
S2, to I
SnFor soft start capacitor C
SCharging and soft start capacitor C
SDischarge.Therefore, only need use single soft start capacitor C in the present invention
SWith single electrical pin P
SCan produce n soft-start signal V
S1, V
S2, to V
Sn
Sequencing circuit 23 has the circuit of energizing 24, a charging/discharging control circuit 25, a charge switch circuit 26 and a discharge switching circuit 27.Connect suitable extraneous power supply and after obtaining to operate required power, the circuit 24 of energizing produces the first enabling signal EN1 immediately and is supplied to the first main circuit passage 21-1 in a plurality of passage integrated circuit (IC) chip 20.
Along with energize circuit 24 according to predetermined order produce enabling signal EN1, EN2, to ENn, charging/discharging control circuit 25 produces charging signals SC and discharge signal SD accordingly, in order to control charge switch circuit 26 and discharge switching circuit 27 respectively.Charge switch circuit 26 has switch element 26-1,26-2 that n can independently control, to 26-n, be arranged at soft start current source I accordingly
S1, I
S2, to I
SnWith soft start capacitor C
SBetween, in order to control soft start capacitor C
SCharging.27 of discharge switching circuits are arranged at soft start capacitor C
SAnd between the ground potential, in order to control soft start capacitor C
SDischarge.
The first main circuit passage 21-1 energized and begin the operation after, the first switch element 26-1 of charge switch circuit 26 allows the first soft start current source I
S1To soft start capacitor C
SCharging makes across soft start capacitor C
SThe potential difference at two ends rises gradually, as the first soft-start signal V
S1The first soft-start signal V
S1Be applied to the first main circuit passage 21-1, in order to the restriction inrush current.In case the first main circuit passage 21-1 reaches stable mode of operation, the first switch element 26-1 of charge switch circuit 26 promptly switches to off state, makes the soft-start signal V that wins
S1Be maintained at high level, no longer be associated with across soft start capacitor C
SThe potential difference at two ends.At this moment, discharge switching circuit 27 switches to short-circuit condition, makes soft start capacitor C
SBe discharged to ground potential.As a result, across soft start capacitor C
SThe potential difference at two ends is returned to zero, so that soft start capacitor C
SCan be applicable to the soft start operation of the second main circuit passage 21-2 subsequently.
At soft start capacitor C
SDischarge finish after, the circuit 24 of energizing applies second enabling signal EN2 to the second main circuit passage 21-2.Under the control of charging/discharging control circuit 25, the second switch unit 26-2 of charge switch circuit 26 allows the second soft start current source I
S2To soft start capacitor C
SCharging makes across soft start capacitor C
SThe potential difference at two ends rises gradually, as the second soft-start signal V
S2The second soft-start signal V
S2Be applied to the second main circuit passage 21-2, in order to the restriction inrush current.In case the second main circuit passage 21-2 reaches stable mode of operation, the second switch unit 26-2 of charge switch circuit 26 promptly switches to off state, makes the second soft-start signal V
S2Be maintained at high level, no longer be associated with across soft start capacitor C
SThe potential difference at two ends.At this moment, discharge switching circuit 27 switches to short-circuit condition, makes soft start capacitor C
SBe discharged to ground potential.As a result, across soft start capacitor C
SThe potential difference at two ends is returned to zero, so that soft start capacitor C
SCan be applicable to the soft start operation of x main circuit passage 21-x subsequently.This variable x is an integer and satisfies inequality n 〉=x 〉=1.Till repetition aforementioned operation program is all finished soft start up to all main circuit passage 21-1,21-2, to 21-n.
Fig. 3 has shown the flow chart according to the soft-start method in regular turn of a plurality of circuit paths of the present invention.In step S1, be applied to the first main circuit passage 21-1 and charging/discharging control circuit 25 and carry out since the first enabling signal EN1 according to soft-start method in regular turn of the present invention.In step S2, discharge switching circuit 27 forms and opens circuit.In step S3, charge switch circuit 26 allows the first soft start current source I
S1For soft start capacitor C
SCharging is in order to produce the first soft-start signal V
S1In step S4, the circuit 24 of energizing judges whether the first main circuit passage 21-1 reaches stable mode of operation.If the mode of operation that Shang Weida is stable then later continues execution in step S3.In case reach stable mode of operation, then execution in step S5, S6 and S7.In step S5, charge switch circuit 26 forms and opens circuit, and stops soft start capacitor C
SCharging.In step S6, discharge switching circuit 27 forms short circuit and makes soft start capacitor C
SBe discharged to ground potential.In step S7, x enabling signal ENx is applied to x main circuit passage 21-x, and wherein this variable x is an integer and satisfies inequality n 〉=x 〉=1.
In step S8, discharge switching circuit 27 forms and opens circuit, and stops soft start capacitor C
SDischarge.In step S9, charge switch circuit 26 allows x soft start current source I
SxFor soft start capacitor C
SCharging is in order to produce x soft-start signal V
SxIn step S10, the circuit 24 of energizing judges whether x main circuit passage 21-x reaches stable mode of operation.If the mode of operation that Shang Weida is stable then later continues execution in step S9.In case reach stable mode of operation, then execution in step S11.All do not reach under the situation of stable mode of operation repeating step S5 to S11 as yet at n main circuit passage 21-1,21-2, to 21-n.That is according to the predetermined order y main circuit passage of energizing, wherein variable y is not equal to the integer of variable x and satisfies inequality n 〉=y 〉=1.In case all main circuit passage 21-1,21-2, all reach stable mode of operation to 21-n, charge switch circuit 26 forms and opens circuit to stop soft start capacitor C
SCharging (step S12), discharge switching circuit 27 form short circuit makes soft start capacitor C
SBe discharged to ground potential (step S13) and circuit 24 output of energizing is ready for surely as signal RDY (step S14), in order to indicate all main circuit passage 21-1,21-2, all to have reached stable mode of operation to 21-n, therefore finish method effectively according to a plurality of circuit paths of soft start in regular turn of the present invention.
Fig. 4 has shown the circuit diagram according to an example of sequencing circuit 23 of the present invention.As shown in the figure, energize circuit 24 based on feedback signal V
Fb1, V
Fb1, to V
FbnJudge present main circuit passage 21-1,21-2, to the mode of operation of 21-n give charging/discharging control circuit 25 so that issue an order.Because feedback signal V
Fb1, V
Fb1, to V
FbnPurpose be to indicate main circuit passage 21-1,21-2, to the mode of operation of 21-n, so feedback signal V
Fb1, V
Fb1, to V
FbnCan be converted by output signal OUT1, OUT2, to OUTn.For example, under the situation of a plurality of passage integrated circuit (IC) chip 20 voltage regulators, output signal OUT1, OUT2, be voltage after overregulating to OUTn, and feedback signal V
Fb1, V
Fb1, to V
FbnMust be for utilizing resitstance voltage divider from output signal OUT1, OUT2, to dividing potential drop that OUTn obtained.
Particularly, the circuit 24 of energizing is implemented by n voltage comparator CV1, CV2, to CVn, and each voltage comparator is in order to judge whether a corresponding main circuit passage reaches steady state operation.For example, the first voltage comparator CV1 has a non-inverting input, in order to receive the first feedback signal V
Fb1(being proportional to the first output signal OUT1), and an inverting input are in order to receive first a predetermined reference voltage V
Ref1When the first main circuit passage 21-1 reaches steady state operation, first feedback voltage V
Fb1Can surpass the first reference voltage V
Ref1, trigger the first voltage comparator CV1 thus.
Charging/discharging control circuit 25 is implemented by combinatorial circuit, in order to determine how to control charge switch circuit 26 and discharge switching circuit 27 according to the judgement of the circuit 24 of energizing.In charge switch circuit 26, switch element 26-1, the 26-2 that n can independently control, all implemented by a transmission lock (Transmission Gate) to each of 26-n, be connected in soft start current source I accordingly
S1, I
S2, to I
SnWith soft start capacitor C
SBetween.27 of discharge switching circuits must be implemented by a nmos pass transistor.
In the embodiment shown in fig. 4, though the circuit 24 of energizing produces enabling signal by means of the mode of operation that detects the main circuit passage, the invention is not restricted to this.The circuit 24 of energizing also can produce each required enabling signal according to a pre-set time interval in regular turn by means of timing circuit or counter.In the case, the timing circuit of the circuit 24 of energizing must be designed to have the function of programmable, makes things convenient for the generation order and mutual length blanking time of each enabling signal of manufacturer and user energy elasticity change enabling signal.
Though the present invention is illustrated as illustration by means of preferred embodiment, be interpreted as: the invention is not restricted in these the disclosed embodiments.On the contrary, this invention is intended to contain tangible for those skilled in the art various modifications and similar configuration.Therefore, the scope of claim should be according to the widest annotation, and this type of is revised and similar configuration to contain all.