The master-slave mode current dividing circuit
Technical field
The present invention relates to a kind of active and slave current distributor circuit, particularly relate to a kind of active and slave current distributor circuit that is applied to the power supply unit parallel system.
Background technology
See also Fig. 1 (a), it is the active and slave current distributor circuit that is applied to the power supply unit parallel system in the known technology, wherein, active and slave current distributor circuit 1 is made of jointly voltage amplifier 11, impedance 12, power conversion stage unit 13, current detecting unit 14, equivalent diode 15, adjustable amplifier 16 and 17 of adder units.Be electrically connected with power supply unit PS1, the PS2 of two parallel connections by active and slave current distributor circuit 1, with the output voltage of reaching stable allocation power supply unit PS1, PS2 and the purpose of output current.
In the parallel system that power supply unit PS1, PS2 are constituted, PS1 normally exports when power supply unit, and the mode that power supply unit PS2 inserts (hot-plugging) with heat is when adding parallel system, can cause the surging phenomenon of waveform generation one signal too drastic (overshoot) of the output voltage of power supply unit PS1, shown in Fig. 1 (b).Yet, owing to the adjustable output voltage Δ V of adjustable amplifier 16 can add to its output voltage V o via active and slave current distributor circuit 1, form Vo+ Δ V, and this surging can be reflected in verily also on the output voltage of parallel system, causes the instability of power supply delivery quality.
In order to overcome this problem, it is as follows to have occurred two kinds of solutions in the known technology:
(1) the adjustable output extreme value Δ V of the adjustable amplifier 16 of reduction
Max, the output voltage V o+ Δ V that just reduction can be reflected in parallel system like this
MaxOn the surging composition.Yet, if with adjustable output extreme value Δ V
MaxDowngrade the degree of the output voltage difference that is lower than power supply unit PS1, PS2, then can cause two power supply units can't constitute parallel system, the situation that active and slave current distributor circuit 1 can't operate.Therefore, the adjustable output extreme value Δ V that utilizes this method to downgrade
MaxBe extremely limited.
(2) in active and slave current distributor circuit 1, add a soft starting circuit (soft-start circuit), be reflected in the surging composition of parallel system with reduction.Yet this method still has shortcoming, see also Fig. 1 (c), it reduces the oscillogram of the surging composition of active and slave current distributor circuit for utilizing soft starting circuit in the known technology, since the running starting point of the soft starting circuit that it adopted is a point, the meaning from figure promptly be not since 0 and soft start be synchronized with the output voltage V o of parallel system, therefore can make soft start function still have the surging of a little to produce inadequately fully, its size then depends on the rise of output voltage time (rising time) of PS2, and rise time fast more then surging composition is big more.
Summary of the invention
In view of the defective in the above-mentioned known technology, master-slave mode current dividing circuit of the present invention has been proposed.
Of the present invention mainly being contemplated that proposes a kind of active and slave current distributor circuit, be applied in the power supply unit parallel system, wherein this power supply unit parallel system is formed in parallel by one first power supply unit and a second source supply at least, and this active and slave current distributor circuit comprises: a voltage amplifier; One power conversion stage unit, one input end are connected in an output of this voltage amplifier, and the one output is connected in a load; One current detecting unit, one input end are connected in this output and this load of this power conversion stage unit; One equivalent diode, one input end are connected in an output of this current detecting unit, and the one output is connected in this power supply unit parallel system; One adjustable amplifier, one reverse input end are connected in this output of this current detecting unit and this input of this equivalence diode, and the one non-inverting input is connected in this output and this power supply unit parallel system of this equivalence diode; One adder unit is connected in a non-inverting input of this voltage amplifier and an output of this adjustable amplifier; One soft starting circuit is connected in this voltage amplifier and this adjustable amplifier; Wherein, feed back to this soft starting circuit by an output voltage that this active and slave current distributor circuit is exported to this load, start this soft starting circuit and be synchronized with a ratio value of this output voltage, when after this first power supply unit, working, in the surge voltage value that this output voltage produced to reduce this second source supply.
According to above-mentioned conception, wherein this voltage amplifier also has a negative-feedback circuit.
According to above-mentioned conception, wherein this negative-feedback circuit is made of an impedance.
According to above-mentioned conception, wherein this ratio value is 90%~95%.
According to above-mentioned conception, wherein also has an energy gap (gap) voltage modulation unit between this non-inverting input of this output of this current detecting unit and this adjustable amplifier, an energy gap voltage that is had between this non-inverting input in order to this output of this current detecting unit of modulation and this adjustable amplifier.
According to above-mentioned conception, wherein this energy gap voltage modulation unit increases this energy gap voltage during less than a default value in this load, and downgrade this energy gap voltage during more than or equal to this default value in this load, to eliminate a wild effect that is produced when this first power supply unit and this second source supply are parallel to underloading.
According to above-mentioned conception, wherein this output of this current detecting unit also is connected in an active voltage and downgrades (Active Droop) unit.
According to above-mentioned conception, wherein this active voltage downgrades the unit in order in this load during less than this default value, downgrade the operating voltage reference value that this active and slave current distributor circuit is had, to reduce an error that is produced when this first power supply unit and this second source supply are parallel to underloading.
According to above-mentioned conception, wherein this operating voltage reference value is 1%~5% of this output voltage.
The present invention is able to more detailed understanding by following accompanying drawing and detailed description.
Description of drawings
Fig. 1 (a) is the active and slave current distributor circuit that is applied to the power supply unit parallel system in the known technology;
Fig. 1 (b) is the surging phenomenon oscillogram of Fig. 1 (a);
Fig. 1 (c) is the soft start oscillogram of another known technology;
Fig. 2 (a) is the active and slave current distributor circuit block diagram of a preferred embodiment of the present invention;
Fig. 2 (b) is the soft start oscillogram of Fig. 2 (a);
Fig. 3 (a) is the active and slave current distributor circuit block diagram (downgrading the unit with energy gap voltage modulation unit and active voltage) of another preferred embodiment of the present invention;
Fig. 3 (b) is the energy gap voltage modulation unit modulation oscillogram of Fig. 3 (a);
Fig. 3 (c) is the oscillogram (not having energy gap voltage modulation unit) before the error in parallel of Fig. 3 (a) reduces;
Fig. 3 (d) is the oscillogram (only having energy gap voltage modulation unit) after the error in parallel of Fig. 3 (a) reduces;
Fig. 3 (e) is that the active voltage of Fig. 3 (a) downgrades unit modulation oscillogram;
Fig. 3 (f) is the oscillogram (downgrading the unit with energy gap voltage modulation unit and active voltage) after the error in parallel of Fig. 3 (a) reduces; And
Fig. 4 is the practical circuit diagram of the active and slave current distributor circuit of the another preferred embodiment of the present invention.
Each element numbers that is comprised in the accompanying drawing of the present invention is described as follows:
1,2,3,4 active and slave current distributor circuits
11,21,31 voltage amplifiers
12,22,32 impedances
13,23,33 power conversion stage unit
14,24,34 current detecting units 24
15,25,35 equivalent diodes
16,26,36 adjustable amplifiers
17,27,37 adder units
28,38,42 soft starting circuits
391,41 energy gap voltage modulation unit
392,43 active voltages downgrade the unit
PS1 first power supply unit
PS2 second source supply
Embodiment
See also Fig. 2 (a), it is the active and slave current distributor circuit block diagram of a preferred embodiment of the present invention, and wherein, active and slave current distributor circuit 2 is applied in the first power supply unit PS1 and the second source supply PS2 power supply unit parallel system that constitutes in parallel.Active and slave current distributor circuit 2 is made of voltage amplifier 21, impedance 22, power conversion stage unit 23, current detecting unit 24, diode 25, adjustable amplifier 26, adder unit 27 and soft starting circuit 28.
Wherein, the input of power conversion stage unit 23 is connected in the output of voltage amplifier 21, output then is connected in a load, the input of current detecting unit 24 is connected in output and this load of power conversion stage unit 23, the input of equivalent diode 25 is connected in the output of current detecting unit 24, output then is connected in the first power supply unit PS1 and second source supply PS2, the reverse input end of adjustable amplifier 26 is connected in the output of current detecting unit 24 and the input of equivalent diode 25, non-inverting input then is connected in output and the first power supply unit PS1 and the second source supply PS2 of equivalent diode 25, adder unit 27 is connected in the non-inverting input of voltage amplifier 21 and the output of adjustable amplifier 26, and 28 of soft starting circuits are connected in voltage amplifier 21 and adjustable amplifier 26.
Feed back to soft starting circuit 28 by an output voltage that active and slave current distributor circuit 2 is exported to this load, the start-up point of soft starting circuit 28 is located at b point (seeing also Fig. 2 (b)) and is synchronized with 90% (ratio value of suggestion) of this output voltage, so that when effectively reducing mode that second source supply PS2 inserts with heat adding parallel system in first power supply unit PS1 work, cause the surge voltage value on the waveform of output voltage of power supply unit PS1.As the oscillogram of Fig. 2 (b) as can be known, the start-up point of soft starting circuit 28 be located at this output voltage be the b point and be synchronized with this output voltage 90%~95% in, the surge voltage value on the output voltage waveforms of power supply unit PS1 and second source supply PS2 is just effectively suppressed.
See also Fig. 3 (a), it is for the active and slave current distributor circuit block diagram of another preferred embodiment of the present invention, wherein, active and slave current distributor circuit 3 also optionally has energy gap voltage modulation unit 391 and active voltage respectively or simultaneously and downgrades (Active Droop) unit 392.
Energy gap voltage modulation unit 391 is connected between the non-inverting input of the output of current detecting unit 34 and adjustable amplifier 36, an energy gap voltage that is had between the non-inverting input in order to the output of modulation current detecting unit 34 and adjustable amplifier 36.Its modulating method is (please cooperate and consult Fig. 3 (b)), increase this energy gap voltage during less than a default value in this load, or downgrade this energy gap voltage during more than or equal to this default value in this load, eliminating a wild effect that is produced when the first power supply unit PS1 and second source supply PS2 are parallel to underloading, and reduce error in parallel between the two in heavy condition.Oscillogram before and after error in parallel reduces is respectively shown in Fig. 3 (c) and 3 (d).
Active voltage downgrades the output that unit 392 is connected in current detecting unit 34, its modulating method is (please cooperate and consult Fig. 3 (e)), in this load during less than this default value (underloading), downgrade the operating voltage reference value that active and slave current distributor circuit 3 is had, just peaked 1%~5% of this output voltage, make that the operation linear gradient of active and slave current distributor circuit 3 is Δ V (=Vo * A)/(Io * B), A=1%~5% (ratio value) wherein, and B=5%~10% (ratio value), this is the operation linear gradient of suggestion, wherein Δ V is active and slave current distributor circuit 3 spendable voltage ranges, and Vo is this output voltage.
This method can promote the operation linearity and the accuracy of active and slave current distributor circuit 3, make that active and slave current distributor circuit 3 can be under the comparatively loose situation of the output voltage difference of less load and the first power supply unit PS1 and second source supply PS2, reduce by error that the first power supply unit PS1 produced when in parallel with second source supply PS2 under a underloading condition.Its oscillogram is shown in Fig. 3 (f).
See also Fig. 4, it is the practical circuit diagram of the active and slave current distributor circuit of the another preferred embodiment of the present invention, wherein the frame of broken lines of the top is represented energy gap voltage modulation unit 41, and the frame of broken lines of below represents that active voltage downgrades unit 43, and middle frame of broken lines is represented soft starting circuit 42.Active and slave current distributor circuit 4 is on actual disposition, energy gap voltage modulation unit 41 and active voltage downgrade that unit 43 can optionally be distinguished or simultaneously and soft starting circuit 42 configurations, effect with the play stably first power supply unit PS1 and second source supply PS2 state in parallel, wherein UVLO represents the brownout locking, OP represents amplifier, and Buff represents buffer.
The present invention can carry out various modifications by those skilled in the art, yet it all should be encompassed within the claim of the present invention.