Voltage Conversion Circuit and Method, and Multiphase Parallel Power System

Abstract

A voltage conversion circuit and method, and a multiphase parallel power system, where in the voltage conversion circuit, a feedback circuit provides a frequency-controllable feedback ripple signal. Therefore, the voltage conversion circuit has a controllable operating frequency, and a frequency requirement of a load may be met. Compensation does not need to be performed in a hysteresis mode, and therefore the hysteresis mode has a fast-speed response. The operating frequency is fixed. Therefore, the voltage conversion circuit in the embodiments may be applied to the multiphase parallel power system such that the multiphase parallel power system is applicable to an application scenario with a large load current.

What is claimed is: 
     
         1 . A voltage conversion circuit comprising:
 a voltage conversion subcircuit comprising:
 a power transistor; 
 a first energy storage element coupled to the power transistor; and 
 a second energy storage element coupled to the power transistor; and 
   a feedback loop coupled to the voltage conversion subcircuit and comprising:
 a sampling and amplification circuit configured to:
 sample a direct current voltage at a coupling end of the first energy storage element and the second energy storage element; and 
 output a first signal; 
 
 a feedback circuit configured to:
 sample the direct current voltage at the coupling end; 
 obtain a sample signal; 
 combine the sample signal with a triangular wave signal; and 
 output a second signal; and 
 
 a comparator circuit configured to:
 compare the first signal with the second signal; and 
 generate a pulse width modulated (PWM) signal, the PWM signal controlling conduction or cutoff of the power transistor. 
 
   
     
     
         2 . The voltage conversion circuit of  claim 1 , wherein the triangular wave signal and the PWM signal are both frequency-controllable, and the second signal is a frequency-controllable feedback ripple signal. 
     
     
         3 . The voltage conversion circuit of  claim 2 , wherein the feedback circuit comprises:
 a triangular wave signal generator configured to generate the frequency-controllable triangular wave signal;   a frequency control subcircuit coupled to the triangular wave signal generator and configured to enable the frequency of the frequency-controllable feedback ripple signal to be the same as a frequency of the frequency-controllable triangular wave signal; and   a direct current control subcircuit coupled to the frequency control subcircuit and configured to control a direct current component voltage of the frequency-controllable feedback ripple signal according to the direct current voltage and a direct current component of the frequency-controllable triangular wave signal.   
     
     
         4 . The voltage conversion circuit of  claim 3 , wherein the frequency control subcircuit comprises a first capacitor and a second capacitor, the direct current control subcircuit comprising a first resistor and a second resistor, the triangular wave signal generator being coupled to the comparator circuit using the first capacitor, the second capacitor being coupled between the comparator circuit and the coupling end of the first energy storage element and the second energy storage element, the first resistor being coupled between the comparator circuit and the coupling end of the first energy storage element and the second energy storage element, and the second resistor being coupled between the comparator circuit and a ground terminal. 
     
     
         5 . The voltage conversion circuit of  claim 1 , wherein the sampling and amplification circuit comprises a bleeder sampling circuit and an error amplification circuit coupled to the bleeder sampling circuit. 
     
     
         6 . The voltage conversion circuit of  claim 5 , wherein the bleeder sampling circuit is configured to:
 perform bleeder sampling on the direct current voltage to obtain a bleeder sampling signal; and   input the bleeder sampling signal to the error amplification circuit.   
     
     
         7 . The voltage conversion circuit of  claim 6 , wherein the error amplification circuit is configured to:
 compare the bleeder sampling signal with a preset reference voltage signal;   amplify a difference signal of the bleeder sampling signal and the preset reference voltage signal to obtain the first signal; and   input the first signal to the comparator circuit.   
     
     
         8 . The voltage conversion circuit of  claim 7 , wherein the bleeder sampling circuit comprises a third resistor and a fourth resistor, the third resistor being coupled between the error amplification circuit and the coupling end of the first energy storage element and the second energy storage element, and the fourth resistor being coupled between the error amplification circuit and a ground terminal. 
     
     
         9 . The voltage conversion circuit of  claim 1 , wherein the feedback loop further comprises a logic circuit and a drive circuit, an output end of the comparator circuit being coupled to the power transistor by successively using the logic circuit and the drive circuit, the logic circuit being configured to compare the PWM signal with a preset control logic signal to obtain a control signal using which the conduction and the cutoff of the power transistor are controlled, and the drive circuit being configured to:
 convert the control signal into a drive signal that has a current driving capability; and   set the drive signal to control the conduction and the cutoff of the power transistor.   
     
     
         10 . The voltage conversion circuit of  claim 1 , wherein the power transistor comprises a first power transistor and a second power transistor, the second power transistor being cut off when the first power transistor is conducted, the second power transistor being conducted when the first power transistor is cut off, the first energy storage element and the second energy storage element being coupled to the first power transistor and the second power transistor, the second energy storage element being charged through the first energy storage element when the first power transistor is conducted and the second power transistor is cut off, and the second energy storage element being configured to discharge through the first energy storage element using the second power transistor when the first power transistor is cut off and the second power transistor is conducted. 
     
     
         11 . The voltage conversion circuit of  claim 1 , wherein the power transistor comprises a first power transistor and a second power transistor, the second power transistor being cut off when the first power transistor is conducted, the second power transistor being conducted when the first power transistor is cut off, the first energy storage element and the second energy storage element being coupled to the first power transistor and the second power transistor, when the first power transistor is conducted and the second power transistor is cut off, the first energy storage element being configured to store energy, and the second energy storage element being configured to discharge, and when the first power transistor is cut off and the second power transistor is conducted, the first energy storage element being configured to release energy using the second power transistor, and the second energy storage element being charged. 
     
     
         12 . The voltage conversion circuit of  claim 1 , wherein the power transistor comprises a first power transistor, a second power transistor, a third power transistor, and a fourth power transistor, the second power transistor being cut off when the first power transistor is conducted, the second power transistor being conducted when the first power transistor is cut off, the fourth power transistor being cut off when the third power transistor is conducted, the fourth power transistor being conducted when the third power transistor is cut off, the first energy storage element and the second energy storage element being coupled to the third power transistor and the fourth power transistor, the first energy storage element being further coupled to the first power transistor and the second power transistor, when the first power transistor is conducted and the second power transistor is cut off, the first energy storage element being configured to store energy, and the second energy storage element being configured to discharge when the third power transistor is conducted and the fourth power transistor is cut off, and the first energy storage element being configured to release energy using the fourth power transistor, and the second energy storage element being charged through the first energy storage when the third power transistor is cut off and the fourth power transistor is conducted, and when the third power transistor is cut off and the fourth power transistor is conducted, the second energy storage element being charged through the first energy storage element when the first power transistor is conducted and the second power transistor is cut off, and the second energy storage element being configured to discharge through the first energy storage element using the second power transistor when the first power transistor is cut off and the second power transistor is conducted. 
     
     
         13 . The voltage conversion circuit of  claim 1 , wherein the power transistor comprises a first power transistor, a second power transistor, a third power transistor, and a fourth power transistor, the second power transistor being cut off when the first power transistor is conducted, the second power transistor being conducted when the first power transistor is cut off, the fourth power transistor being cut off when the third power transistor is conducted, and the fourth power transistor being conducted when the third power transistor is cut off. 
     
     
         14 . The voltage conversion circuit of  claim 13 , wherein the first energy storage element and the second energy storage element are coupled to the third power transistor and the fourth power transistor, the first energy storage element being further coupled to the first power transistor and the second power transistor, and when the first power transistor is conducted and the second power transistor is cut off, the first energy storage element is configured to store energy. 
     
     
         15 . The voltage conversion circuit of  claim 14 , wherein the second energy storage element is configured to discharge when the third power transistor is conducted and the fourth power transistor is cut off, and the first energy storage element being configured to release energy using the fourth power transistor. 
     
     
         16 . The voltage conversion circuit of  claim 15 , wherein the second energy storage element is charged through the first energy storage when the third power transistor is cut off and the fourth power transistor is conducted. 
     
     
         17 . The voltage conversion circuit of  claim 16 , wherein when the third power transistor is cut off and the fourth power transistor is conducted, the second energy storage element is charged through the first energy storage element when the first power transistor is conducted and the second power transistor is cut off. 
     
     
         18 . The voltage conversion circuit of  claim 17 , wherein the second energy storage element is configured to discharge through the first energy storage element using the second power transistor when the first power transistor is cut off and the second power transistor is conducted. 
     
     
         19 . A voltage conversion method, applied by a feedback loop comprising a sampling and amplification circuit, a feedback circuit, and a comparator circuit, the method comprising:
 sampling, by the sampling and amplification circuit, a direct current voltage at a coupling end of a first energy storage element and a second energy storage element of a voltage conversion subcircuit;   outputting, by the sampling and amplification circuit, a first signal based on the direct current voltage;   obtaining, by the feedback circuit, a sample signal by sampling the direct current voltage at the coupling end of the first energy storage element and the second energy storage element of the voltage conversion subcircuit;   combine, by the feedback circuit, the sample signal with a triangular wave signal to output a second signal; and   compare, by the comparator circuit, the first signal with the second signal to generate a pulse width modulated (PWM) signal, the PWM signal controlling conduction or cutoff of a power transistor of the voltage conversion subcircuit.   
     
     
         20 . The voltage conversion method of  claim 19 , wherein the triangular wave signal and the PWM signal are both frequency-controllable, and the second signal is a frequency-controllable feedback ripple signal.