Buck-Store and Boost-Restore Converter

Abstract

A buck-store and boost-restore converter is to be electrically connected to a pre-stage circuit, which provides a pre-stage output direct current (DC) voltage to a first capacitive load. The converter has an inductance element and is to be electrically connected to a second capacitive load. When the pre-stage output DC voltage is reduced from a first DC voltage to a second DC voltage, the inductance element outputs a current to the second capacitive load so as to transfer electric energy, which is stored in the first capacitive load, to the second capacitive load. When the pre-stage output DC voltage is raised from the second DC voltage to the first DC voltage, the inductance element outputs a current to the first capacitive load so as to transfer electric energy, which is stored in the second capacitive load, to the first capacitive load.

1 . A buck-store and boost-restore converter to be electrically connected to a pre-stage circuit and a first capacitive load, wherein the pre-stage circuit receives a pre-stage input DC voltage and provides a pre-stage output DC voltage to the first capacitive load, and the pre-stage output DC voltage comprises a first DC voltage or a second DC voltage, characterized in that:
 the converter has an inductance element and is to be electrically connected to a second capacitive load;   when the pre-stage output DC voltage is reduced from the first DC voltage to the second DC voltage, the inductance element serves as a current source with a variable current to output a current to the second capacitive load, so as to transfer electric energy, stored in the first capacitive load, to the second capacitive load; and   when the pre-stage output DC voltage is raised from the second DC voltage to the first DC voltage, the inductance element serves as a current source with a variable current to output a current to the first capacitive load, so as to transfer electric energy, stored in the second capacitive load, to the first capacitive load.   
     
     
         2 . A buck-store and boost-restore converter to be electrically connected to a pre-stage circuit and a first capacitive load, wherein the pre-stage circuit receives a pre-stage input DC voltage and provides a pre-stage output DC voltage to the first capacitive load, and the pre-stage output DC voltage comprises a first DC voltage or a second DC voltage, the converter comprising:
 an input terminal, to be coupled to the first capacitive load, for receiving the pre-stage output DC voltage;   a first switch coupled to the input terminal;   an inductance element having a first end coupled to the first switch;   a second switch coupled between the inductance element and a constant voltage; and   an output terminal coupled to a second end of the inductance element and a second capacitive load, wherein:   when the pre-stage output DC voltage is reduced from the first DC voltage to the second DC voltage, the converter enters a buck-store operation mode and the first switch and the second switch are alternately turned on, so that the inductance element outputs a current to the second capacitive load to transfer electric energy, stored in the first capacitive load, to the second capacitive load; and   when the pre-stage output DC voltage is raised from the second DC voltage to the first DC voltage, the converter enters a boost-restore operation mode and the first switch and the second switch are alternately turned on, so that the inductance element outputs a current to the first capacitive load to transfer electric energy, stored in the second capacitive load, to the first capacitive load.   
     
     
         3 . The converter according to  claim 2 , wherein in the buck-store operation mode, the first switch is turned on before the second switch is turned on. 
     
     
         4 . The converter according to  claim 2 , wherein in the boost-restore operation mode, the second switch is turned on before the first switch is turned on. 
     
     
         5 . The converter according to  claim 2 , further comprising:
 a first current sensor, coupled to the first switch, for sensing a current flowing through the inductance element; and   a second current sensor, coupled to the second switch, for sensing the current flowing through the inductance element.   
     
     
         6 . The converter according to  claim 5 , wherein in the buck-store operation mode, the first switch is turned off when the first current sensor senses that the current of the inductance element exceeds an upper bound value, and the second switch is turned off when the second current sensor senses that the current of the inductance element is substantially equal to zero. 
     
     
         7 . The converter according to  claim 5 , wherein in the boost-restore operation mode, the second switch is turned off when the second current sensor senses that the current of the inductance element exceeds an upper bound value, and the first switch is turned off when the first current sensor senses that the current of the inductance element is substantially equal to zero. 
     
     
         8 . The converter according to  claim 2 , wherein the constant voltage is a ground voltage. 
     
     
         9 . The converter according to  claim 2 , wherein the pre-stage circuit is a DC-DC converter. 
     
     
         10 . The converter according to  claim 2 , wherein the pre-stage circuit receives a power of a solar energy electrode plate. 
     
     
         11 . The converter according to  claim 2 , wherein the pre-stage circuit is a low drop regulator. 
     
     
         12 . The converter according to  claim 2 , wherein the converter is further selectively controlled under a pulse width modulation (PWM) operation. 
     
     
         13 . The converter according to  claim 2 , wherein the converter is further selectively controlled under a pulse frequency modulation (PFM) operation. 
     
     
         14 . The converter according to  claim 2 , wherein the converter is further selectively controlled under a sigma-delta modulation operation. 
     
     
         15 . The converter according to  claim 2 , wherein the converter further selectively provides electric energy to a post-stage circuit. 
     
     
         16 . The converter according to  claim 2 , wherein the pre-stage output DC voltage is provided to a plurality of light-emitting diodes (LEDs) connected in series. 
     
     
         17 . The converter according to  claim 2 , wherein the pre-stage output DC voltage is provided to a central processing unit (CPU). 
     
     
         18 . A system, comprising:
 a pre-stage circuit for receiving a pre-stage input DC voltage from a power source, and providing a pre-stage output DC voltage, wherein the pre-stage output DC voltage comprises a first DC voltage or a second DC voltage;   a first capacitive load for receiving the pre-stage output DC voltage;   a second capacitive load; and   a buck-store and boost-restore converter electrically connected to the pre-stage circuit and the first capacitive load, the converter comprising:
 an input terminal, coupled to the first capacitive load, for receiving the pre-stage output DC voltage; 
 a first switch coupled to the input terminal; 
 an inductance element having a first end coupled to the first switch; 
 a second switch coupled between the inductance element and a constant voltage; and 
 an output terminal coupled to a second end of the inductance element and further coupled to the second capacitive load, 
   wherein when the pre-stage output DC voltage is reduced from the first DC voltage to the second DC voltage, the converter enters a buck-store operation mode and the first switch and the second switch are alternately turned on, so that the inductance element outputs a current to the second capacitive load to transfer electric energy, stored in the first capacitive load, to the second capacitive load.   
     
     
         19 . The system according to  claim 18 , wherein when the pre-stage output DC voltage is raised from the second DC voltage to the first DC voltage, the converter enters a boost-restore operation mode and the first switch and the second switch are alternately turned on, so that electric energy of the second capacitive load serves as electric energy outputted from the pre-stage circuit.