CN101083432B - Single electric inductance multiplex output boosted circuit - Google Patents

Abstract

The invention discloses a single-inductance multioutput boosted circuit, using shutdown current generating module to generate modulation control signals of a switch array, to control ON/OFF of multichannel power switch transistors in the switch array, so as to implement multi-input to multi-output DC/DC boosting conversion. As compared with the existing technique, it can use a circuit composed of fewer components to obtain multiple DC boosted outputs and improve circuit integrity, raise circuit efficiency and reduce the making cost.

Description

Single electric inductance multiplex output boosted circuit

Technical field

The present invention relates to a kind of pulse frequency modulated type (PFM) DC/DC transducer, especially relate to and in circuit, adopt single inductance coil, by the charge/discharge control strategy of switch arrays, realize plurality of voltages output result's DC/DC booster circuit to power switch pipe.

Background technology

The DC/DC transducer is small and exquisite, cheap because of its volume, and outstanding features such as energy conversion efficiency height are in core status always in the design of energy-efficient Switching Power Supply, be widely used in various power-supply management systems.Many microelectric technique companies leading in the world such as Linear Technology, Maxim, Analog Devices, NationalSemiconductor etc., all dropped into lot of manpower and material resources in the DC/DC field, develop the conversion chip that numerous species is various, function is different, particularly in today of portable set develop rapidly, power-supply system more and more trends towards miniaturization, high efficiency, intellectuality, makes all big enterprises strengthen the research and development for the efficient DC/DC conversion of low-voltage and high-current chip one after another.Be accompanied by the constantly demand of development of industry, DC/DC converter technique and relevant chip method for designing are also brought in constant renewal in the replacement, and various control strategies cleverly emerge in an endless stream.In the step-up DC/DC converter of PFM (pulse frequency modulated) working method, its input links to each other with the drain electrode of N channel power switching transistor by a coil, connects with the lead-out terminal that is connected load by a diode from this tie point.At the two ends of load, filter capacitor in parallel.Different with described PWM working method converter is, removed error amplifier, increased the AND circuit, and replaced triangular-wave generator with oscillator, again the AND circuit is imported in the output of this oscillator and the output of comparator together, control described power switch transistor by the umber of pulse of its output, thus control output voltage.

Wherein, the most common with the pattern of single channel input/single channel output.And if can in a DC/DC circuit, utilize the single channel input signal to obtain a plurality of output results simultaneously, then can improve the service efficiency of the type circuit greatly.This is a technical problem to be solved in the present invention.

Summary of the invention

In view of above-mentioned technical problem, of the present inventionly proposed a kind of single inductance and exported booster circuit more, utilize the cut-off current generation module to produce the modulator control signal of switch arrays, in order to the unlatching and the shutoff of multichannel power switch transistor in the control switch array, thereby realize that multichannel is input to the DC/DC boost conversion of output.

Single inductance of the present invention is exported booster circuit more, comprise that time sequence control logic module, first channel button and second channel button, error amplifier, cut-off current produce circuit and switch arrays, wherein: the output voltage of first channel button and second channel button is as the two-way differential input signal of differential amplifier, output result feedback after differential amplifier is handled sends the time sequence control logic module to, is used to adjust the sequential mistake; Output a4, the b4 of time sequence control logic module, c4 are as influencing the input signal that cut-off current produces the circuit sequence control logic, to the generation sequential completion logic control of cut-off current; Produce in the circuit at cut-off current,, calculate each road reference current Iref according to the reference voltage Vref that loads on this circuit;

These switch arrays comprise power supply (Input Power Supply), and the voltage that provides these switch arrays required is provided, and this positive source inductance (Inductor) of connecting is used to produce the required electric current of these switch arrays, power cathode ground connection; Power supply is by an above-mentioned inductance and a N tube power switch in parallel, and makes N tube power switch drain (Drain) link to each other N tube power switch source (Source) ground connection with above-mentioned inductance one end; Also comprise the multichannel output circuit that boosts in the switch arrays, each road booster circuit comprises a P tube power switch (P-Switch), a current sensor (Out-current-sensor), each P tube power switch is opened one by one from the high voltage to the low-voltage, when the input current of P tube power switch equates with Iref, turn-off the P pipe; The source electrode (Source) of described each P tube power switch links to each other with inductance output end, and be connected respectively to the signal input part of the pairing current sensor of every road booster circuit, the output of current sensor is input a1, b1, the c1 of on/off current generating circuit respectively, be used to detect the cut-off current on every road, when turn-off corresponding P tube power switch with decision; By each signal a3, b3, the c3 that the time sequence control logic circuit provides, be connected respectively to the grid of the p tube power switch of each road booster circuit, when grid (CNT) is 0V, source electrode is connected with drain electrode, when grid (CNT) is high, source electrode disconnects with drain electrode, substrate is received the current potential that is higher than source electrode.

The present invention compared with prior art, the circuit that can utilize components and parts still less to form obtains the output of a plurality of DC boosting, can improve the integrated level of circuit, has improved the efficient of circuit, has saved manufacturing cost.

Description of drawings

Fig. 1 is the circuit structure diagram of single electric inductance multiplex output boosted circuit involved in the present invention.

Fig. 2 is the circuit structure diagram of switch array involved in the present invention.

Embodiment

Below in conjunction with the drawings and specific embodiments technical scheme of the present invention is further described embodiment: single inductance of the present invention is exported booster circuit more, comprises that time sequence control logic module (Timing control logic), channel button (Channel select switch), error amplifier (Error Signal Comparator), cut-off current produce circuit (off-current-setup) and switch arrays (Switch Array).Wherein, the output voltage of first channel button and second channel button is as the two-way differential input signal of differential amplifier, and the effect of differential amplifier is the common-mode feedback voltage that suppresses two channel buttons.Therefore, the differential amplifier role here is to reduce signal errors.Output result feedback after differential amplifier is handled sends the time sequence control logic module to, and the sequential that takes place when being used to adjust time sequence control logic is adjusted mistake.

The output a4 of time sequence control logic module, b4, c4 is as influencing the input signal that cut-off current produces the circuit sequence control logic, to the generation sequential completion logic control of cut-off current.Produce in the circuit at this cut-off current,, and utilize following formula, calculate multichannel reference current Iref according to the reference voltage Vref that loads on this circuit.

Iref calculates:

I _ref＝I _ref(d)·K _d+I _ref(b)·K _b+I _ref(c)·Kc+I _ref(a)·K _a

K _a, K _b, K _cRelevant with the output voltage difference, when output voltage is higher than reference voltage K _xBe 0, otherwise be 1.

$I_{\mathrm{ref}}\left(d\right)=\frac{R_d\·\mathrm{\Δ}{V}_d\·K_d}{N_d(V_d-V_i)}+\frac{R_c\·\mathrm{\Δ}{V}_c\·K_c}{N_c(V_d-V_i)}+\frac{R_b\·\mathrm{\Δ}{V}_b\·K_b}{N_b(V_d-V_i)}+\frac{R_a\·\mathrm{\Δ}{V}_a\·K_a}{N_a(V_d-V_i)}$

$I_{\mathrm{ref}}\left(c\right)=\frac{R_c\·\mathrm{\Δ}{V}_c\·K_c}{N_c(V_c-V_i)}+\frac{R_b\·\mathrm{\Δ}{V}_b\·K_b}{N_b(V_c-V_i)}+\frac{R_b\·\mathrm{\Δ}{V}_b\·K_b}{N_a(V_c-V_i)}+\frac{R_a\·V_a\·K_a}{N_c(V_d-V_i)}$

$I_{\mathrm{ref}}\left(b\right)=\frac{R_b\·\mathrm{\Δ}{V}_b\·K_b}{N_b(V_b-V_i)}+\frac{R_a\·\mathrm{\Δ}{V}_a\·K_a}{N_a(V_b-V_i)}$

$I_{\mathrm{ref}}\left(a\right)=\frac{R_a\·\mathrm{\Δ}{V}_a\·K_a}{N_a(V_a-V_i)}$

K _a, K _b, K _c, K _dBe respectively the modulation factor that each road (a, b, c, d) needs charging to export, its value is 1 or 0;

Δ V _a, Δ V _b, Δ V _c, Δ V _dBe respectively that A to D puts output voltage error;

N _a, N _b, N _c, N _dIt is respectively the design current ratio of A to D point;

(V _a-V _i), (V _b-V _i), (V _c-V _i), (V _d-V _i) be respectively A to D point input-output voltage difference.

Single inductance multichannel booster circuit of the present invention, the core of this circuit is switch arrays, these switch arrays comprise power supply (Input Power Supply), the voltage that provides these switch arrays required is provided, this positive source inductance (Inductor) of connecting, be used to produce the required electric current of these switch arrays, power cathode ground connection; Positive source is by an inductance and a N tube power switch in parallel, and N tube power switch drain (Drain) is linked to each other with inductance one end, N tube power switch source (Source) ground connection, and high level is opened, as the master switch of whole switch arrays unlatching/shutoff.Also comprise the multichannel output circuit that boosts in the switch arrays, each road booster circuit comprises a P tube power switch (P-Switch), a current sensor (Out-current-sensor), each P tube power switch is opened to the low-voltage pointwise from high voltage, when the input current of P tube power switch equates with Iref, turn-off the P pipe.Its source electrode (S) is in parallel with inductance output end, and be connected respectively to the signal input part of the pairing current sensor of every road booster circuit, the output of current sensor is input a1, b1, the c1 of on/off current generating circuit respectively, be used to detect the cut-off current on every road, when turn-off corresponding P tube power switch with decision.P tube power switch, its course of work rely on its four extremely to finish, i.e. source electrode (Source), substrate (Bulk), drain electrode (Drain), grid (Cnt).This P tube power switch is the gate MOS assembly that low level is opened.Input signal a3, the b3 of time sequence control logic circuit, c3 are connected respectively to the grid of the p tube power switch of each road booster circuit, and when grid CNT is " 0V ", source electrode is connected with drain electrode; When grid CNT is " height ", source electrode disconnects with drain electrode.When source electrode was connected with drain electrode, the conducting resistance of P tube power switch can be subjected to the influence of underlayer voltage, and when underlayer voltage was higher than source voltage, conducting resistance raise, and voltage is high more, and conducting resistance is high more.BULK is connect this output point can reduce conducting resistance.Obtain multichannel output voltage V to each charging capacitor charging that each P tube power switch drain connects this moment _a, V _b, V _c, V _dAnd when source electrode disconnects with drain electrode,, will have leakage current to flow to drain electrode by substrate if the source electrode output voltage is higher than the drain electrode output voltage.For the P pipe is turn-offed, substrate must be received the current potential that is higher than source electrode.When certain was not opened, this substrate connect ceiling voltage point (A point).When this P switching tube was opened, its substrate connect this output point.The each point switching tube opening time is by setting reference current control, and when the electric current by switch during smaller or equal to reference current, switching tube turn-offs.

Claims (1)

1. a single inductance is exported booster circuit more, comprise that time sequence control logic module, first channel button and second channel button, error amplifier, cut-off current produce circuit and switch arrays, wherein: the output voltage of first channel button and second channel button is as the two-way differential input signal of differential amplifier, output result feedback after differential amplifier is handled sends the time sequence control logic module to, is used to adjust the sequential mistake; The output of time sequence control logic module (a4, b4, c4) is as influencing the input signal that cut-off current produces the circuit sequence control logic, to the generation sequential completion logic control of cut-off current; Produce in the circuit at cut-off current,, calculate each road reference current Iref according to the reference voltage Vref that loads on this circuit;

These switch arrays comprise power supply (Input Power Supply), and the voltage that provides these switch arrays required is provided, and this positive source inductance (Inductor) of connecting is used to produce the required electric current of these switch arrays, power cathode ground connection; Power supply is by an above-mentioned inductance and a N tube power switch in parallel, and makes N tube power switch drain (Drain) link to each other N tube power switch source (Source) ground connection with above-mentioned inductance one end; Also comprise the multichannel output circuit that boosts in the switch arrays, each road booster circuit comprises a P tube power switch (P-Switch), a current sensor (Out-current-sensor), each P tube power switch is opened one by one from the high voltage to the low-voltage, when the input current of P tube power switch equates with Iref, turn-off the P pipe; The source electrode (Source) of described each P tube power switch links to each other with inductance output end, and be connected respectively to the signal input part of the pairing current sensor of every road booster circuit, the output of current sensor is the input (a1, b1, c1) of on/off current generating circuit respectively, be used to detect the cut-off current on every road, when turn-off corresponding P tube power switch with decision; By each signal (a3, b3, c3) that the time sequence control logic circuit provides, be connected respectively to the grid of the p tube power switch of each road booster circuit, when grid (CNT) is 0V, source electrode is connected with drain electrode, when grid (CNT) is high, source electrode disconnects with drain electrode, substrate is received the current potential that is higher than source electrode.

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