CN107979266B - Single-inductance double-output switch converters voltage-type-capacitance current ripple mixing control method and device - Google Patents

Abstract

The invention discloses a voltage type-capacitor current ripple hybrid control method and device for a single-inductance double-output switching converter. The voltage-type controller CTR ₁ detects the output voltage V _oa of the single-inductance dual-output switching converter, and generates a control pulse Vgs ₁ for controlling the conduction and shut-off of the branch switching tube S ₁ in the single-inductance dual-output switching converter ; The capacitor current ripple controller CTR ₂ detects the output voltage V _ob , the a-way capacitor current I _c1 and the b-way capacitor current I _c2 of the single-inductor dual-output switching converter, and generates a control pulse Vgs ₂ for controlling the single-inductor dual-output switching converter Turn-on and turn _- off of the main switch S2 in the output switching converter. The beneficial effect of the present invention is that the single-inductance dual-output switching converter can quickly adjust the control pulse of the main switching tube when the load changes, the output voltage overshoot is small, the adjustment time is short, and the load transient performance of the converter is better ; When the load of the output branch changes, it can effectively reduce the cross effect of one output branch.

Description

Voltage type-capacitor current ripple hybrid control method for single-inductor dual-output switching converter method and device

technical field

The invention relates to the technical field of switching converters, in particular to a voltage-type-capacitor current ripple hybrid control method and device for a single-inductance dual-output switching converter.

Background technique

With the widespread popularity of portable electronic products such as smart phones and tablet computers, users have higher and higher requirements for the size, cost and efficiency of their power supplies. Studies have shown that single-inductor dual-output switching converters can provide two independent power supplies for portable electronic products such as smartphones and tablet computers, reducing the number of inductors and control chips, effectively reducing the size of the power supply and reducing production costs. , which improves the conversion efficiency, thus attracting more and more attention from academia and industry.

The traditional voltage type-peak current hybrid control, its control idea is: the control circuit includes a voltage type control circuit and a peak current control circuit, the voltage type control circuit compares the detected output voltage with the reference voltage, and the output error signal passes through the error amplifier After compensation, the amplified error voltage is obtained, and the amplified error voltage is compared with the sawtooth wave voltage by a comparator to output a control signal to control the branch switch tube of the main circuit. The peak current control circuit includes a voltage control loop and a current control loop. The voltage control loop samples another output voltage and compares it with the reference voltage. The output error signal is compensated by the error amplifier to obtain an amplified error voltage. The current control loop compares the sampled inductor current with the amplified error voltage through the comparator. The comparison result and the clock signal are used as the input signals of the R terminal and the S terminal of the RS flip-flop respectively, and the Q terminal of the RS flip-flop outputs the control signal to control the main switch of the main circuit. Tube. This method is used in a single-inductance dual-output converter, which has the disadvantages of serious crossover effect between output branches and slow load transient response.

Contents of the invention

The purpose of the present invention is to provide a control method and device for a single-inductance dual-output switching converter, so that it has better load transient performance and smaller output cross effects at the same time, and is suitable for single-inductance dual-output switching converters various topologies.

The technical scheme that realizes the object of the present invention is as follows:

A voltage type-capacitor current ripple hybrid control method for a single inductor dual output switching converter, the voltage type controller CTR ₁ detects the output voltage V _oa of the single inductor dual output switching converter and generates a control pulse Vgs ₁ for controlling the single inductor _The switching on and off of the branch switching tube S1 in the dual-output switching converter; the capacitor current ripple controller CTR ₂ detects the output voltage V _ob of the single-inductance dual-output switching converter, the capacitor currents I _c1 and b of the a circuit The circuit capacitor current I _c2 generates a control pulse Vgs ₂ to control the turn-on and turn-off of the main switch S ₂ in the single-inductance dual-output switching converter.

Further, the generation method of the control pulse Vgs ₁ is as follows: the output voltage V _oa and the voltage reference value V _ref1 generate an amplified error signal V _c1 through the error amplifier EAP ₁ and send it to the positive input terminal of the comparator CMP ₁ , and the sawtooth wave is generated The sawtooth wave V _m generated by the device STH is sent to the negative input terminal of the comparator CMP ₁ , and V _c1 and V _m generate the control pulse Vgs ₁ through the comparator CMP ₁ ; the generation method of the control pulse Vgs ₂ is: the output voltage V _ob And the voltage reference value V _ref2 passes through the error amplifier EAP ₂ to generate an amplified error signal V _c2 and sends it to the negative input terminal of the comparator CMP ₂ , and the capacitance current I _c1 and the capacitance current I _c2 pass through the adder ADD to obtain the total capacitance current I _c and send it to input to the positive input of the comparator CMP ₂ ; the comparison result of I _c and V _c2 is sent to the R terminal of the RS flip-flop TGR to control the shutdown of the main switch S2 _; the clock signal CLK is sent to the S terminal of the RS flip-flop TGR , to control the conduction of the main switch _S2 .

A voltage type-capacitor current ripple hybrid control device for a single inductance dual output switching converter, including a voltage type controller CTR ₁ and a capacitor current ripple controller CTR ₂ ; the voltage type controller CTR ₁ includes sequentially connected voltage detection circuits VS ₁ , error amplifier EAP ₁ , comparator CMP ₁ and drive circuit DR ₁ , and a sawtooth generator STH connected to CMP ₁ ; EAP ₁ is also connected to a reference voltage V _ref1 ; the capacitor current ripple controller CTR ₂ includes A voltage detection circuit VS ₂ , an error amplifier EAP ₂ , a comparator CMP ₂ , an RS flip-flop TGR and a drive circuit DR ₂ connected in sequence; and a capacitive current detection circuit IS ₁ and a capacitive current detection circuit IS respectively connected to the adder ADD ₂ , ADD is also connected to CMP ₂ ; EAP ₂ is also connected to the reference voltage V _ref2 , and TGR is also connected to the clock signal CLK; the VS ₁ , VS ₂ , IS ₁ , IS ₂ , DR ₁ and DR ₂ are respectively connected to the single Inductive dual output switching converter.

Further, the single-inductor dual-output switching converter is a Buck converter, a Boost converter, a Buck-Boost converter or a Bipolar converter.

Compared with prior art, the beneficial effect of the present invention is:

1. Compared with the existing voltage type-peak current hybrid control single-inductance dual-output switching converter, the single-inductance dual-output switching converter of the present invention can quickly adjust the control pulse of the main switching tube and output The voltage overshoot is small, the adjustment time is short, and the load transient performance of the converter is better.

2. Compared with the existing voltage type-peak current hybrid control single-inductance dual-output switching converter, the single-inductance dual-output switching converter of the present invention can effectively reduce the load of one output branch when the load of the output branch changes. Road crossing effects.

Description of drawings

Fig. 1 is a system structure diagram of the present invention.

Fig. 2 is a circuit structure diagram when the Buck converter is used in the present invention.

Fig. 3 is a waveform diagram of the inductor current and the control pulse of the switching device when the Buck converter is used in the present invention. Among them, Fig. 3a is the control pulse waveform of the inductor current and the switching device when d ₁ <d ₂ , that is, the continuous conduction mode of the inductor current rising _- rising-falling _; - Inductor current and switching device control signal waveforms in drop-down continuous conduction mode.

Fig. 4 is the transient time-domain simulation waveforms of the present invention and the voltage type-peak current hybrid control single-inductance dual-output switching converter when the loads of the output branches a and b change respectively. Among them, Fig. 4a is the transient response waveform of the voltage-type-peak current hybrid control single-inductance dual-output switching converter when the load of the output branch a changes; Fig. 4b is the transient response of the present invention when the load of the output branch a changes Waveform; Figure 4c is the transient response waveform of the voltage type-peak current hybrid control single-inductance dual-output switching converter when the load of the output branch b changes; Figure 4d is the transient response of the present invention when the load of the output branch b changes waveform.

Detailed ways

The basic idea of voltage type-capacitor current ripple hybrid control is that the control circuit includes a voltage type control circuit and a capacitor current ripple control circuit. The voltage type control circuit is the same as the above analysis, and is used to control the branch switch tube of the main circuit. The capacitor current ripple control circuit also includes a voltage control loop and a current control loop. The voltage control loop samples the output voltage and compares it with the reference voltage. The output error signal is compensated by the error amplifier to obtain an amplified error voltage. The current control loop compares the sampled capacitor current with the amplified error voltage through the comparator, the comparison result and the clock signal are used as the input signals of the R terminal and the S terminal of the RS flip-flop respectively, and the Q terminal of the RS flip-flop outputs a control signal to control the main switch of the main circuit Tube. The voltage type-capacitor current ripple hybrid control single-inductance dual-output converter has the advantages of small output cross effect and good load transient performance.

The present invention will be described in further detail below in conjunction with the accompanying drawings.

As shown in Figure 1, the voltage-type-capacitor current ripple hybrid control method and device for a single-inductor dual-output switching converter is composed of a converter TD and a control device for switching tubes S ₁ and S ₂ . Its control device is mainly composed of a voltage controller CTR ₁ and a capacitor current ripple controller CTR ₂ . The voltage type controller CTR ₁ is composed of a voltage detection circuit VS ₁ , a reference voltage V _ref1 , an error amplifier EAP ₁ , a sawtooth wave generator STH, a comparator CMP ₁ , and a drive circuit DR ₁ ; the capacitor current ripple controller CTR ₂ is composed of a voltage Detection circuit VS ₂ , capacitance current detection circuit IS ₁ , capacitance current detection circuit IS ₂ , adder ADD, reference voltage V _ref2 , error amplifier EAP ₂ , comparator CMP ₂ , RS flip-flop TGR, drive circuit DR ₂ , clock signal CLK composition. Among them, the voltage detection circuits VS ₁ and VS ₂ are used to obtain the output voltages V _oa and V _ob respectively, the capacitance current detection circuits IS ₁ and IS ₂ are used to obtain the capacitance currents I _c1 and I _c2 respectively, and the adder ADD is used to obtain the total the capacitor current, the error amplifiers EAP ₁ and EAP ₂ are used to obtain the amplified error voltages V _c1 and V _c2 respectively, the sawtooth wave generator STH is used to obtain the sawtooth wave V _m , and the comparator CMP ₂ is used to obtain the RS flip-flop TGR ₂ The R terminal input signal, the clock signal CLK is used as the S terminal input signal of the RS flip-flop TGR, the Q terminal output signal of the RS flip-flop TGR is used to obtain the control signal of the switch tube S ₂ , and the comparator CMP ₁ is used to obtain the switch tube S The control signal of ₁ controls the turn-on and turn-off of the switching tube of the switching converter TD through the driving circuits DR ₁ and DR ₂ .

The converter TD in this example is a Buck converter, and its working process and principle are:

The working process and principle of the control device adopting voltage type-capacitor current ripple hybrid control are as follows: Figure 2 shows that the voltage type controller CTR ₁ samples the output voltage V _oa , and the comparison result with the reference voltage V _ref1 passes through the error amplifier EAP ₁ The amplified error voltage V _c1 is obtained; V _c1 and the sawtooth wave V _m generated by the sawtooth generator STH pass through the comparator CMP ₁ , and output a control signal V _{gs1 to} control the switch tube S ₁ . The capacitor current ripple controller CTR ₂ samples the output voltage V _ob and the capacitor current I _c1 , I _c2 ; the comparison result of the output voltage V _ob and the reference voltage V _ref2 passes through the error amplifier EAP ₂ to obtain an amplified error voltage V _c2 ; the capacitor current I _c1 and I _c2 obtain the total capacitive current I _c through the adder ADD; I _c and V _c2 are compared with the comparator CMP ₂ to obtain the R terminal input signal of the RS flip-flop TGR, and TGR generates the turn-off signal of the main switch S ₂ It is connected to the input end of the driving circuit DR ₂ , and the output end of DR ₂ is connected to the gate control end of the main switching tube S ₂ to control the switching off of the switching tube S ₂ .

FIG. 3 shows the working sequence and the waveform diagram of the inductor current when the circuit in FIG. 2 works in the continuous conduction mode of the inductor current. When the working sequence of the converter is shown in Figure 3a, within the time of d _1a T _s , S ₁ and S ₂ are turned on, D ₁ and D ₂ are turned off, and the inductor current flows through the output branch a at the charging slope (V _in -V _oa ) /L rises. During (d _2a -d _1a ) T _s time, S ₂ and D ₂ are turned on, S ₁ and D ₁ are turned off, and the inductor current continues to rise through the output branch b with a charging slope of (V _in -V _ob )/L . During (1-d _2a ) T _s time, D ₁ and D ₂ are turned on, S ₁ and S ₂ are turned off, and the inductor current drops through the output branch b with the discharge slope -V _ob /L. When the working sequence of the converter is shown in Figure 3b, during the time d _2b T _s , S ₁ and S ₂ are turned on, D ₁ and D ₂ are turned off, and the inductor current flows through the output branch a at the charging slope (V _in -V _oa ) /L rises. During (d _1b -d _2b ) T _s time, S ₁ and D ₁ are turned on, S ₂ and D ₂ are turned off, and the inductor current drops through the output branch a with the discharge slope -V _oa /L. During (1-d _1b )T _s time, D ₁ and D ₂ are turned on, S ₁ and S ₂ are turned off, and the inductor current flows through the output branch b with a discharge slope -V _ob /L until the circuit enters the next switching cycle.

Use PSIM simulation software to carry out time domain simulation analysis to the method of the present invention, the result is as follows.

Fig. 4 is a time-domain simulation waveform diagram of the output voltage and output current when the load of the output branch is suddenly changed by using the voltage type-peak current hybrid control and the present invention is implemented in a single-inductance dual-output Buck converter. Fig. 4a and Fig. 4b respectively correspond to the voltage Type-peak current hybrid control and voltage type-capacitor current ripple hybrid control are the time-domain simulation waveforms of the output voltage and output current when the load of the output branch a of the single-inductance dual-output Buck converter changes. Figure 4c and Figure 4d correspond to the voltage-type -Peak current hybrid control and voltage type-capacitor current ripple hybrid control The time-domain simulation waveforms of output voltage and output current when the load of the output branch b of the single-inductance dual-output Buck converter changes. In Figure 4a and Figure 4b, the output current I _oa of the output branch a of the output branch a of the single-inductance dual-output Buck converter with voltage-peak current hybrid control and voltage-capacitor current ripple control changes suddenly from 1A To 1.5A, when the output current I _oa of the output branch b is 1A, the cross influence of the voltage type-peak current hybrid control single inductance double output output branch a on the output branch b is 200mV; and adopting the voltage type of the present invention - Capacitor-current ripple hybrid control The cross effect of output branch a on output branch b of single-inductance dual-output Buck switching converter is about 50mV. In Fig. 4c and Fig. 4d, the output current I _ob of the output branch b of the output branch b of the single-inductance dual-output Buck converter with voltage-peak current hybrid control and voltage-capacitor current ripple control changes suddenly from 1A When the output current I _oa of the output branch a is 1.5A, the output voltage V _ob of the output branch b of the output branch b of the voltage type-peak current hybrid control single-inductance dual-output Buck converter enters a new steady state after about 3ms, The overshoot is 200mV; while the transient adjustment time of the voltage type-capacitor current ripple hybrid control single-inductance double-output Buck converter of the present invention is very short, and the overshoot is 50mV. It can be seen that the transient overshoot of the output voltage of the output branch b of the switching converter of the present invention is small, the adjustment time is short, the load transient performance is good, and the cross influence of the output branch a on the output branch b is small. The simulation conditions in Fig. 4 are input voltage V _in = 10V, reference voltage V _ref1 = 1.8V, V _ref2 = 3.3V, inductance L = 100μH, capacitance C ₁ = 470μF, C ₂ = 220μF, load resistance R _a = 1.8Ω , _Rb = 3.3Ω.

In the present invention, the converter TD may also be a Boost converter, a Buck-Boost converter or a Bipolar converter.

Claims (4)

1. single-inductance double-output switch converters voltage-type-capacitance current ripple mixing control method, which is characterized in that voltage-type Controller CTR₁Detect the single-inductance double-output switch converters output voltage V_oa, generate control pulse Vgs₁, to control Branch switch pipe S in single-inductance double-output switch converters₁Conducting and shutdown；Capacitance current ripple control device CTR₂Detection institute State single-inductance double-output switch converters output voltage V_ob, the road a capacitance current I_c1With the road b capacitance current I_c2, generate control pulse Vgs₂, to control main switch S in single-inductance double-output switch converters₂Conducting and shutdown.

2. the method as described in claim 1, which is characterized in that the control pulse Vgs₁Generation method are as follows: output voltage V_oaWith voltage reference value V_ref1By error amplifier EAP₁Generate the error signal V of amplification_c1It is sent into comparator CMP₁It is just defeated Enter end, the sawtooth wave V that saw-toothed wave generator STH is generated_mIt is sent into comparator CMP₁Negative input end, V_c1And V_mPass through comparator CMP₁Generate control pulse Vgs₁；The control pulse Vgs₂Generation method are as follows: output voltage V_obWith voltage reference value V_ref2Through Cross error amplifier EAP₂Generate the error signal V of amplification_c2It is sent into comparator CMP₂Negative input end, capacitance current I_c1And capacitor Electric current I_c2Total capacitance current I is obtained by adder ADD_cIt is sent into comparator CMP₂Positive input terminal；I_cAnd V_c2Comparison knot Fruit is sent into the end R of rest-set flip-flop TGR, controls main switch S₂Shutdown；Clock signal clk is sent into the end S of rest-set flip-flop TGR, Control main switch S₂Conducting.

3. single-inductance double-output switch converters voltage-type-capacitance current ripple mixed control apparatus, it is characterised in that: including electricity Die mould controller CTR₁With capacitance current ripple control device CTR₂；

The voltage mode control device CTR₁Including the voltage detecting circuit VS being sequentially connected₁, error amplifier EAP₁, comparator CMP₁ With driving circuit DR₁, and it is connected to CMP₁Saw-toothed wave generator STH；EAP₁It is also connected with reference voltage V_ref1；

The capacitance current ripple control device CTR₂Including the voltage detecting circuit VS being sequentially connected₂, error amplifier EAP₂, ratio Compared with device CMP₂, rest-set flip-flop TGR and driving circuit DR₂；It further include the capacitance current detection circuit for being connected respectively to adder ADD IS₁With capacitance current detection circuit IS₂, ADD is also connected to CMP₂；EAP₂It is also connected with reference voltage V_ref2, TGR, which is also connected with clock, to be believed Number CLK；

The VS₁、VS₂、IS₁、IS₂、DR₁And DR₂It is connected respectively to the single-inductance double-output switch converters.

4. device as claimed in claim 3, which is characterized in that the single-inductance double-output switch converters are Buck transformation Device, Boost, One Buck-Boost converter body or Bipolar converter.