Switched capacitor voltage converting device and switched capacitor voltage converting method
A voltage converting device includes first to third voltage converters, each including a capacitor, a pair of charge switches for charging the capacitor, a pair of first output switches for outputting a first output voltage through the capacitor, and a pair of second output switches for outputting a second output voltage through the capacitor. Via timing control of the switches, outputs of the first and second output voltages are substantially continuous and are prevented from floating.
1. A voltage converting device comprising a first voltage converter, a second voltage converter, and a third voltage converter, each of said first voltage converter, said second voltage converter and said third voltage converter including:
a capacitor having a pair of capacitor terminals;
a pair of charge switches each having a first terminal and a second terminal, said first terminals of said charge switches being coupled respectively to said capacitor terminals, said second terminals of said charge switches being disposed to receive first and second charge voltages, respectively;
a pair of first output switches each having a first terminal and a second terminal, said first terminals of said first output switches being coupled respectively to said capacitor terminals, said second terminal of one of said first output switches being disposed to receive a first input voltage, said second terminal of the other one of said first output switches being disposed to output a first output voltage; and
a pair of second output switches each having a first terminal and a second terminal, said first terminals of said second output switches being coupled respectively to said capacitor terminals, said second terminal of one of said second output switches being disposed to receive a second input voltage, said second terminal of the other one of said second output switches being disposed to output a second output voltage; and
a switch controller coupled electrically to said first voltage converter, said second voltage converter and said third voltage converter,
wherein, for each of said first voltage converter, said second voltage converter and said third voltage converter, said switch controller controls said charge switches to make electrical connection simultaneously and to break electrical connection simultaneously, controls said first output switches to make electrical connection simultaneously and to break electrical connection simultaneously, and controls said second output switches to make electrical connection simultaneously and to break electrical connection simultaneously;
wherein, for each of said first voltage converter, said second voltage converter and said third voltage converter, said switch controller controls said charge switches, said first output switches and said second output switches to make electrical connection in a predetermined sequence, and only one pair of said pairs of said charge switches, said first output switches and said second output switches make electrical connection at a time;
wherein said switch controller controls said first output switches of said first voltage converter, said second voltage converter and said third voltage converter such that output of the first output voltage is substantially continuous;
wherein said switch controller controls said second output switches of said first voltage converter, said second voltage converter and said third voltage converter such that output of the second output voltage is substantially continuous; and
wherein said switch controller controls said first voltage converter, said second voltage converter and said third voltage converter in a manner that when said charge switches of one of said first voltage converter, said second voltage converter and said third voltage converter make electrical connection, said first output switches of another one of said first voltage converter, said second voltage converter and said third voltage converter make electrical connection, and said second output switches of yet another one of said first voltage converter, said second voltage converter and said third voltage converter make electrical connection.
2. The voltage converting device as claimed in claim 1 , wherein:
said first terminal of said charge switch that receives the first charge voltage, said first terminal of said first output switch that outputs the first output voltage, and said first terminal of said second output switch that receives the second input voltage are coupled to a same one of said capacitor terminals; and
said first terminal of said charge switch that receives the second charge voltage, said first terminal of said first output switch that receives the first input voltage, and said first terminal of said second output switch that outputs the second output voltage are coupled to the other one of said capacitor terminals.
3. A voltage converting method to be implemented by the voltage converting device as claimed in claim 1 , each of the first voltage converter, the second voltage converter and the third voltage converter of the voltage converting device being operable to switch among a first state to output one of the first output voltage and the second output voltage, a second state to output the other one of the first output voltage and the second output voltage, and a charging state, said voltage converting method comprising the steps of:
a) switching the first voltage converter to the first state, switching the third voltage converter to the second state, and switching the second voltage converter to the charging state in the given sequence;
b) switching the second voltage converter to the first state, switching the first voltage converter to the second state, and switching the third voltage converter to the charging state in the given sequence; and
c) switching the third voltage converter to the first state, switching the second voltage converter to the second state, and switching the first voltage converter to the charging state in the given sequence.
4. The voltage converting method as claimed in claim 3 , wherein the second output voltage is outputted in the first state, and the first output voltage is outputted in the second state.
5. The voltage converting method as claimed in claim 3 , wherein the first output voltage is outputted in the first state, and the second output voltage is outputted in the second state.
6. A voltage converting method to be implemented by a voltage converting device that includes a first voltage converter, a second voltage converter and a third voltage converter, each of the first voltage converter, the second voltage converter and the third voltage converter being a switched capacitor voltage converter, and being operable to switch among a first voltage output state, a second voltage output state, and a charging state, said voltage converting method comprising the steps of:
a) switching the first voltage converter to the first voltage output state, switching the third voltage converter to the second voltage output state, and switching the second voltage converter to the charging state in the given sequence;
b) switching the second voltage converter to the first voltage output state, switching the first voltage converter to the second voltage output state, and switching the third voltage converter to the charging state in the given sequence; and
c) switching the third voltage converter to the first voltage output state, switching the second voltage converter to the second voltage output state, and switching the first voltage converter to the charging state in the given sequence.