TWI399909B - Power conversion system and power control method for reducing different regulation effect - Google Patents

Description

Power conversion system and power supply control method for reducing mutual voltage stabilization effect

The present invention relates to a power conversion system, and more particularly to a power conversion system and a power supply control method for reducing mutual voltage stabilization effects of a single inductor multi-output DC/DC converter.

Today's power management chips are widely used in portable electronic products such as mobile phones, PDAs, and notebook computers. In the trend of system chip development, in order to reduce the chip area, a single-inductor multi-output DC/DC converter architecture will be adopted. However, this multi-output architecture will have problems with poor stability and mutual voltage regulation.

The tradition is mainly to make the multiple outputs independent of each other, so that the output terminals are not interfered by the load changes of each other to solve the mutual voltage regulation effect problem. Continuous pseudo-conduction (Pseudo-CCM) current technology can be used, and the overall system has a state like discontinuous current mode (DCM), which will make the system easy to stabilize. And because it has a zero current equivalent to the discontinuous current mode, there is a buffer phase in each switching cycle, so that the instantaneous load change does not affect the next cycle to reduce the mutual voltage stabilization effect. However, this mode must be added to the Freewheel phase throughout the Pulse Width Modulation (PWM) cycle. Due to the equivalent group effect of the non-ideal turn-on switch, a large amount of power will be consumed during this phase. The conduction loss (Conduction Loss) will increase, which in turn affects the efficiency conversion. In addition, the energy stored in the inductor during the freewheeling phase cannot be transmitted to the output, and the average inductor current will be greater than the sum of the output loads. Due to the discontinuous output inductor current of the single-inductor multi-output module architecture, a large average inductor current will cause a large output voltage ripple. Therefore, a high-performance post-stage voltage regulator circuit is required to further process the output voltage. .

Another approach is to prioritize the energy distribution process. However, this method is only applicable to a specific load state, and it uses the comparator to control the output voltage. Compared with the closed loop, the error amplifier is used for control, and the overall voltage regulation effect is not satisfactory.

In addition, an inductor can be used in conjunction with the charge pump architecture. However, this architecture must additionally use external capacitors and diodes, and there will be a large output voltage ripple. And because the negative voltage output is achieved by the charge pump, the negative voltage output will have a poor voltage regulation, which is quite unsatisfactory in practical applications.

In view of the above, the present invention is directed to the above-mentioned problems and targets, and at the same time, combining the electronic circuit technology and the energy control concept, proposes a power conversion system and a power supply control method for reducing mutual voltage stabilization effects.

The main object of the present invention is to provide a power conversion system and a power supply control method for reducing the mutual voltage stabilizing effect, which utilizes a voltage feedback adjustment circuit to adjust the error signal to effectively eliminate the mutual voltage stabilization effect and achieve a stable dual output power supply. .

Another object of the present invention is to provide a power conversion system and a power supply control method for reducing the mutual voltage stabilizing effect, which utilizes a pre-detection of an output voltage energy change and a reaction load state change at the output end to quickly adjust the system duty cycle. The system has good output steady state and transient response, and the power conversion efficiency is excellent.

Another object of the present invention is to provide a power conversion system and a power supply control method for reducing mutual voltage stabilization effects, which can be integrated into various power management modules, and the practical application level is extremely wide.

In order to achieve the above object, the power conversion system for reducing the mutual voltage stabilization effect of the present invention comprises a switching circuit, a current detector, a plurality of error amplifiers, a voltage feedback adjustment circuit, a peak generator, A comparator group and a control circuit. The switch circuit is electrically connected to at least one inductor, and the charge and discharge of the control inductor is turned on and off by the switch circuit to output a plurality of output voltages, and the inductor current flowing through the inductor is detected by the current detector to sense Inductor voltage. And the error amplifier receives the feedback output voltage and calculates the error signal of the input voltage. The voltage feedback adjustment circuit receives and modulates the error signal to generate a plurality of error modulation signals. And the error modulation signal will be received by the peak generator to generate a peak voltage. And comparing the error modulation signal and the peak voltage and the inductor voltage with the inductor voltage by the comparator group to generate a plurality of voltage signals, and the voltage signal is received by the control circuit to generate a plurality of control signals for controlling the switch circuit and controlling the inductance Charge and discharge.

The power control method for reducing mutual voltage stabilization effect proposed by the present invention comprises the steps of: first, calculating respective error signals of a plurality of output voltages according to load states of the plurality of output voltages. After that, the error signal is modulated, the energy of the output voltage according to the load state is calculated, and a plurality of error modulation signals are generated. Then, the peak voltage is calculated according to the error modulation signal, and the total energy value of the charge and discharge cycle is calculated by the peak voltage, so that the total energy of the charging cycle is the total energy required by the system, and the total energy of the discharge cycle is the output voltage. The sum of energy. Finally, charging to at least one inductor based on the peak voltage, the inductor will store the total energy of the charging cycle.

The purpose, technical contents, features and effects achieved by the present invention will be more readily understood by the detailed description of the embodiments and the accompanying drawings.

The invention provides a power conversion system and a power supply control method for reducing the mutual voltage stabilizing effect, which utilizes feedback control to detect the change of the energy of the output end in advance when the load state of the output changes, so that the system can adjust the responsibility according to the load state. Cycles, quickly driving steady state, to reduce the occurrence of the Cross Regulation. The technical features of the present invention will be described in detail below with reference to preferred embodiments.

The first figure is a schematic diagram of the circuit architecture of the present invention. As shown in the figure, a switch circuit 50 is electrically connected to at least one inductor L, which includes a plurality of transistor switches M ₁ , M ₂ and M ₃ , and a control transistor switch. M ₁ , M ₂ and M ₃ turn on or off to control the charge and discharge of the inductor L to output a positive output voltage (V _op ) and a negative output voltage (V _on ). The inductor current flowing through the inductor L is detected by a current detector 52 to sense the inductor voltage (V _s ) of the inductor L.

The output positive output voltage (V _op ) and the negative output voltage (V _on ) are respectively divided into resistance voltages via resistors (R _p1 ) and resistors (R _p1 ) and resistors (R _n1 ) and resistors (R _n1 ). V _fp ) and the feedback voltage (V _fn ) are fed back to the error amplifiers (EA) 54 and 56, and the error amplifiers (EA) 54 and 56 are based on the reference voltage (V _ref ) to generate a positive output voltage error signal ( V _ep ) and negative output voltage error signal (V _en ).

The positive output voltage error signal (V _ep ) and the negative output voltage error signal (V _en ) are received via a voltage feedback adjustment circuit 58 electrically coupled to the error amplifiers (EA) 54 , 56 , which are positive output voltage errors The signal (V _ep ) and the negative output voltage error signal (V _en ) are mutually feedback, and the positive output voltage error signal (V _ep ) is used to adjust the voltage level by using the feedback negative output voltage error signal (V _en ). A positive output voltage error modulation signal (V _emp ) is generated; a negative output voltage error signal (V _en ) is a voltage output level modulation using a feedback positive output voltage error signal (V _ep ) to generate a negative output voltage error adjustment Change signal (V _emn ).

The positive output voltage error modulation signal (V _emp ) and the negative output voltage error modulation signal (V _emn ) are further input to a peak generator 60 electrically connected to the voltage feedback adjustment circuit 58 , which utilizes a positive output voltage. The error modulation signal (V _emp ) and the negative output voltage error modulation signal (V _emn ) generate a peak voltage (V _epn ). This peak voltage will be the maximum charge limit during the charging cycle of inductor L.

A comparator group (CMP) 62 is electrically connected to the current detector 52, the voltage feedback adjustment circuit 58 and the peak generator 60, and receives the inductor voltage (V _s ), the peak voltage (V _epn ) and the positive output voltage. The error modulation signal (V _emp ) compares the peak voltage (V _epn ) and the positive output voltage error modulation signal (V _emp ) with the inductor voltage (V _s ) to generate a plurality of voltage signals (V _CAB ) and (V _CA ), and the voltage signals (V _CAB ) and (V _CA ) will be transmitted to a control circuit 64. The control circuit 64 includes a path decision logic 641 and a bias adjustment circuit 642. The path decision logic 641 receives the voltage signals (V _CAB ) and (V _CA ) and the system clock signal (V _clk ), and controls the bias adjustment circuit 642. The control signals V _G1 , V _G2 and V _{G3 are} generated to control the transistor switches M ₁ , M ₂ and M _{3 of the} switch circuit 50 to be turned on or off to achieve charge and discharge of the control inductor L.

In addition, a slope compensator 68 is electrically coupled to the current detector 52 for compensating for subharmonic oscillations caused by variations in the inductor current and for generating a desired system clock signal (V _clk ). And the voltage (V _nn ) on the voltage dividing side of the reference voltage (V _ref ) and the negative output voltage (V _on ) will be generated by a band gap reference circuit 70. And a substrate switching circuit 66 is provided to the transistor switch M _{3 of the} switching circuit 50 to prevent the matrix effect. Additionally, voltage feedback adjustment circuit 58 can be integrated with error amplifiers (EA) 54 and 56.

The above is a detailed description of the circuit system architecture of the present invention, and the power control method of the present invention will be further described below.

The second figure is a flow chart of the power control of the present invention. Please refer to the first figure as shown in the figure. First, as step S10, the error amplifiers (EA) 54 and 56 are based on the output voltage (V _op ) and (V _on The feedback voltages (V _fp ) and (V _fn ) that are fed back by the load state calculate the error signals (V _ep ) and (V _en ) of the output voltage.

Then, in step S12, the voltage feedback adjustment circuit 58 modulates the error signals (V _ep ) and (V _en ) to generate an error modulation signal (V _emp ) and (V _emn ) to make the energy and load state of the output voltage. Compatible.

Next, in step S14, the peak generator 60 calculates the peak voltage (V _epn ) according to the error modulation signals (V _emp ) and (V _emn ), and calculates the total energy value of the charge and discharge cycle by the peak voltage (V _epn ). The peak voltage (V _epn ) is the maximum charging limit of the charging cycle. The total energy of the charging cycle will be the total energy required by the system, and the total energy of the discharging cycle is the sum of the energy of the output voltage.

Finally, as in step S16, charging to the inductance L according to the peak voltage (V _epn ), the inductance L will store the total energy value of the charging period.

The above description of the power control method of the present invention will further explain the effect of reducing the mutual voltage regulation effect by detecting the change of the output voltage energy in advance when the load state fluctuates according to the present invention.

The third figure is a waveform diagram of the charge and discharge cycle of the inductor of the present invention, and please refer to the circuit diagram of the first figure and the power control flow chart of the second figure, and the fourth (a) and fourth (b) Schematic diagram of positive and negative output voltage energy changes, as shown, at steady state, the output voltage energy is negative output voltage energy 20 and positive output voltage energy 22, respectively. Considering that the voltage feedback adjustment circuit 58 is not provided, when the load state of the positive output voltage (V _op ) changes and the load state of the negative output voltage (V _on ) does not change, since the positive output current (I _op ) will Suddenly, the positive output voltage error signal (V _ep ) rises, causing the peak voltage (V _epn ) to rise. Therefore, the negative output voltage energy 20 and the positive output voltage energy 22 will increase to a negative output voltage energy 30 and a positive output voltage energy 32. However, since the load state of the negative output voltage ( _Von ) does not change, the negative output voltage energy 20 does increase to become the negative output voltage energy 30, at which time the mutual voltage regulation effect occurs.

Therefore, when the positive output voltage (V _op ) load state changes by the voltage feedback adjustment circuit 58 and the positive output current (I _op ) increases, the positive output voltage error signal (V _ep ) and the negative output voltage error signal (V _{en )} Modulation, using the mutual feedback method, pull up the positive output voltage error signal (V _ep ) level, become the positive output voltage error modulation signal (V _emp ), and reduce the negative output voltage error signal (V _en ) It becomes a negative output voltage error modulation signal (V _emn ). Thus, the peak voltage (V _epn ) can be _pulled down so that the positive output current (I _op ) changes, the negative output voltage energy 40 is equal to the negative output voltage energy 20, and only the positive output voltage energy 22 is increased to the positive output voltage energy 42. . Therefore, during the same pulse width modulation (PWM) period, the energy obtained by the negative output voltage (V _on ) whose load state has not changed does not change, and the mutual voltage stabilizing effect of the output voltage variation will not occur.

The above is a description of the state in which the positive output voltage (V _op ) load state changes and the positive output current (I _op ) increases. The changes of load current, feedback voltage, error modulation signal and peak voltage under various other load conditions are shown in Table (1). The corresponding energy change situation can be inferred according to the voltage and current changes, and will not be described here.

It can be seen from the above description that the present invention will adjust the error signal by the voltage feedback adjustment circuit 58 to achieve the purpose of detecting the output voltage energy in advance according to the load state. The energy of the charging cycle is the total energy required by the system, and the energy of the output voltage of the unchanging load will remain fixed, greatly eliminating the effect of reducing the mutual voltage regulation, and the system will have excellent output steady state and transient response. In addition, the present invention is applicable to non-isolated boost, buck, buck-boost power conversion circuits and isolated forward, full-bridge, half-bridge, push-pull power conversion circuits, etc. Combination of power conversion circuit and power conversion circuit.

The embodiments described above are merely illustrative of the technical spirit and the features of the present invention, and the objects of the present invention can be understood by those skilled in the art, and the scope of the present invention cannot be limited thereto. That is, the equivalent variations or modifications made by the spirit of the present invention should still be included in the scope of the present invention.

20‧‧‧Negative output voltage energy

22‧‧‧ Positive output voltage energy

30‧‧‧Negative output voltage energy

32‧‧‧ Positive output voltage energy

40‧‧‧Negative output voltage energy

42‧‧‧ Positive output voltage energy

50‧‧‧Switch circuit

52‧‧‧ Current Detector

54‧‧‧Error amplifier

56‧‧‧Error amplifier

58‧‧‧Voltage feedback adjustment circuit

60‧‧‧peak generator

62‧‧‧Comparator group

64‧‧‧Control circuit

641‧‧‧Path Decision Logic

642‧‧‧bias adjustment circuit

66‧‧‧Base switching circuit

68‧‧‧Slope compensator

70‧‧‧Gap reference circuit

The first figure is a schematic diagram of the circuit architecture of the present invention.

The second figure is a flow chart of the power control of the present invention.

The third figure is a waveform diagram of the charge and discharge cycle of the inductor of the present invention.

The fourth (a) diagram is a schematic diagram of the change in the energy of the negative output voltage of the present invention.

The fourth (b) diagram is a schematic diagram of the positive output voltage energy variation of the present invention.

50. . . Switch circuit

52. . . Current detector

54. . . Error amplifier

56. . . Error amplifier

58. . . Voltage feedback adjustment circuit

60. . . Peak generator

62. . . Comparator group

64. . . Control circuit

641. . . Path decision logic

642. . . Bias adjustment circuit

66. . . Substrate switching circuit

68. . . Slope compensator

70. . . Bandgap reference circuit

Claims (17)

A power conversion system for reducing mutual voltage stabilization effects, comprising: a switching circuit electrically connected to at least one inductor, controlling charging and discharging of the inductor to output a plurality of output voltages; and a current detector electrically connected to the An inductor detects an inductor current flowing through the inductor to sense an inductor voltage of the inductor; a plurality of error amplifiers electrically connected to the switch circuit, receiving the output voltage of the feedback, and generating an error signal of the output voltage; a voltage feedback adjustment circuit electrically connected to the error amplifier, receiving the error signal, and modulating the error signal to generate a plurality of error modulation signals; a peak generator electrically connected to the voltage feedback adjustment circuit Receiving the error modulation signal to generate a peak voltage; a comparator group electrically connected to the voltage feedback adjustment circuit and the peak generator and the current detector, receiving the error modulation signal and the peak voltage and the The inductor voltage is compared with the error modulation signal and the peak voltage to generate a plurality of voltage signals; and a control circuit, Electrically connected to the comparators, and receiving the voltage signal, generating a plurality of control signals to control the switching circuit. The power conversion system for reducing the mutual voltage stabilization effect described in claim 1 further includes a slope compensator electrically connected to the current detector to compensate for subharmonic oscillation caused by the variation of the inductor current. . The power conversion system for reducing mutual voltage stabilization effect according to claim 1, wherein the error amplifier amplifies the error signal based on a reference voltage. The power conversion system for reducing the mutual voltage stabilization effect described in claim 3 of the patent application further includes a gap reference circuit for generating the reference voltage. The power conversion system for reducing the mutual voltage stabilization effect according to claim 1, wherein the control circuit further comprises a path decision logic and a bias adjustment circuit, wherein the path decision logic receives the voltage signal to control the bias The voltage adjustment circuit generates the control signal. The power conversion system for reducing mutual voltage stabilization effect according to claim 1, wherein the switch circuit comprises a plurality of transistor switches, and the control signal generated by the control circuit controls the transistor switch to open or close. The power conversion system for reducing the mutual voltage stabilizing effect as described in claim 1, wherein the peak voltage is a maximum charging limit of a charging period of the inductor. The power conversion system for reducing mutual voltage stabilization effect according to claim 1, wherein the output voltage is a positive voltage or a negative voltage. The power conversion system for reducing the mutual voltage stabilization effect according to claim 1, wherein the voltage feedback adjustment circuit is integrated into the error amplifier. A power control method for reducing mutual voltage stabilization effects includes the steps of: calculating respective error signals of a plurality of output voltages; modulating the error signals to generate a plurality of error modulation signals; and calculating a peak voltage according to the error modulation signals And calculate the total energy value of the charge and discharge cycle by the peak voltage. The power control method for reducing the mutual voltage stabilizing effect according to claim 10, wherein in the step of calculating the respective error signals of the plurality of output voltages, the error signal is calculated according to the load state of the output voltage. The power control method for reducing the mutual voltage stabilizing effect according to claim 11, wherein in the step of modulating the error signal, the energy of the output voltage is adjusted by adjusting the error signal to conform to the load state. The power control method for reducing the mutual voltage stabilizing effect according to claim 12, wherein in the step of calculating the peak voltage according to the error modulation signal, the total energy value of the discharge period is the output voltage The sum of this energy. The power supply control method for reducing mutual voltage stabilization effect according to claim 10, wherein the output voltage is a positive voltage or a negative voltage. The power supply control method for reducing mutual voltage stabilization effect according to claim 10, wherein the peak voltage is a maximum charging limit of the charging cycle. The power control method for reducing the mutual voltage stabilizing effect as described in claim 10, wherein the total energy of the charging period is the total energy required by the system. The power control method for reducing the mutual voltage stabilizing effect described in claim 10, further comprising the step of charging to the at least one inductor according to the peak voltage, wherein the inductor stores the total energy value of the charging period.