Signal converter
A signal converter includes a first capacitor, a second capacitor, a first switch to a fourth switch, and a first feedback control circuit to a fourth feedback control circuit. The first switch and the second switch are coupled between a reference voltage end and an output end in series. The first switch and the second switch are respectively controlled by a first feedback control signal and a second feedback control signal. The third switch and a fourth switch are respectively controlled by a third feedback control signal and a fourth feedback control signal. The first feedback control circuit provides the first feedback control signal. The second feedback control circuit provides the second feedback control signal. The third feedback control circuit provides the third feedback control signal. The fourth feedback control circuit provides the fourth feedback control signal.
1 . A signal converter, comprising:
a first capacitor comprising a first end coupled to a first input end receiving a first input signal and a second end;
a second capacitor comprising a third end coupled to a second input end receiving a second input signal and a fourth end;
a first switch and a second switch, coupled between a reference voltage end and an output end in series, the first switch and the second switch being coupled to the second end of the first capacitor, and being respectively controlled by a first feedback control signal and a second feedback control signal;
a third switch and a fourth switch, coupled between the reference voltage end and the output end in series, the third switch and fourth switch being coupled to the fourth end of the second capacitor, and being respectively controlled by a third feedback control signal and a fourth feedback control signal;
a first feedback control circuit, coupled between the second input end and one of the third end and the fourth end of the second capacitor, for providing the first feedback control signal to a control end of the first switch;
a second feedback control circuit, coupled between the first input end and one of the third end and the fourth end of the second capacitor, for providing the second feedback control signal to a control end of the second switch;
a third feedback control circuit, coupled between the first input end and one of the first end and the second end of the first capacitor, for providing the third feedback control signal to a control end of the third switch; and
a fourth feedback control circuit, coupled between the second input end and one of the first end and the second end of the first capacitor, for providing the fourth feedback control signal to a control end of the fourth switch.
2 . The signal converter as claimed in claim 1 , wherein the first input signal and the second input signal are differential radio-frequency signals and the output end outputs a direct current output voltage.
3 . The signal converter as claimed in claim 1 , wherein each of the first to fourth feedback control circuits comprises a diode and a capacitor which are coupled in series.
4 . The signal converter as claimed in claim 3 , wherein the diode is formed by a transistor connecting in diode connection configuration.
5 . The signal converter as claimed in claim 4 , wherein the transistor is a P-type transistor.
6 . The signal converter as claimed in claim 3 , wherein the capacitor is a metal-insulator-metal capacitor, a metal-oxide-metal capacitor, or a metal-oxide-semiconductor capacitor.
7 . The signal converter as claimed in claim 1 , wherein the first feedback control circuit comprises:
a diode, comprising an anode coupled to the control end of the first switch and a cathode coupled to the second input end; and
a third capacitor, comprising one end coupled to the control end of the first switch and the anode of the diode and the other end coupled to either the third end of the second capacitor or the fourth end of the second capacitor.
8 . The signal converter as claimed in claim 1 , wherein the second feedback control circuit comprises:
a diode, comprising an anode coupled to the first input end and a cathode coupled to the control end of the second switch; and
a third capacitor, comprising one end coupled to the control end of the second switch and the cathode of the diode and the other end coupled to either the third end of the second capacitor or the fourth end of the second capacitor.
9 . The signal converter as claimed in claim 1 , wherein the third feedback control circuit comprises:
a diode, comprising an anode coupled to the control end of the third switch and a cathode coupled to the first input node; and
a third capacitor, comprising one end coupled to the control end of the third switch and the anode of the diode and the other end coupled to either the first end of the first capacitor or the second end of the first capacitor.
10 . The signal converter as claimed in claim 1 , wherein the fourth feedback control circuit comprises:
a diode, comprising an anode coupled to the second input node and a cathode coupled to the control end of the fourth switch; and
a third capacitor, comprising one end coupled to the control end of the fourth switch and the cathode of the diode and the other end coupled to either the first end of the first capacitor or the second end of the first capacitor.
11 . The signal converter as claimed in claim 1 , wherein the first switch to the fourth switch are respectively formed by a first transistor to a fourth transistor.
12 . The signal converter as claimed in claim 11 , wherein a doping type of the first transistor and a doping type of the second transistor are complementary, a doping type of the third transistor and a doping type of the fourth transistor are complementary.
13 . The signal converter as claimed in claim 12 , wherein the doping types of the first transistor and the third transistor are same.