CPC H02J 7/00712 (2020.01) [H02J 7/0013 (2013.01); H02M 1/08 (2013.01); H02M 3/155 (2013.01)] | 17 Claims |
1. A step-down circuit, comprising:
a positive input terminal and a negative input terminal for receiving an input voltage;
a positive output terminal and a negative output terminal for outputting a target voltage, wherein the negative input terminal and the negative output terminal are grounded together;
a switch circuit comprising at least one switch connected between the positive input terminal and the negative input terminal, wherein the switch circuit comprises a first switch (Q1), a second switch (Q2), and a third switch (Q3) connected in series between the positive input terminal and the negative input terminal;
a rectifier circuit comprising at least one switch connected between the positive output terminal and the negative output terminal, wherein the rectifier circuit is a full-bridge rectifier circuit comprising a fourth switch (Q4), a fifth switch (Q5), a sixth switch (Q6), and a seventh switch (Q7), the fourth switch (Q4) and the fifth switch (Q5) are connected in series between the positive output terminal and the negative output terminal, and the sixth switch (Q6) and the seventh switch (Q7) are connected in series between the positive output terminal and the negative output terminal;
an isolation circuit comprising at least one capacitor connected to the at least one switch in the switch circuit and the at least one switch in the rectifier circuit, wherein the isolation circuit comprises a first capacitor (C1) and a second capacitor (C2), one end of the first capacitor (C1) is connected to a common connection node between the first switch (Q1) and the second switch (Q2), the other end of the first capacitor (C1) is connected to a common connection node between the fourth switch (Q4) and the fifth switch (Q5), one end of the second capacitor (C2) is connected to a common connection node between the second switch (Q2) and the third switch (Q3), and the other end of the second capacitor (C2) is connected to a common connection node between the sixth switch (Q6) and the seventh switch (Q7); and
a control unit configured to output control signals to control the at least one switch in the switch circuit to be turned on or off, and to control the at least one switch in the rectifier circuit to be turned on or off, to cause that the input voltage sequentially passes through the at least one switch in the switch circuit, the at least one capacitor in the isolation circuit, and the at least one switch in the rectifier circuit to obtain the target voltage, wherein a voltage value of the target voltage is lower than a voltage value of the input voltage.
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