Signal conversion circuit
View Patent ↗A signal conversion circuit for converting an inputted differential signal into a single-ended signal comprises a differential amplifier circuit for amplifying the differential signal, and generating a first non-inverted signal and a first inverted signal being inverted the first non-inverted signal, a first inverter for generating a second non-inverted signal being inverted the first inverted signal and an interpolation unit for interpolating a phase difference between the first non-inverted signal and the second non-inverted signal.
1. A signal conversion circuit for converting an inputted differential signal into a single-ended signal, comprising:
a differential amplifier circuit for amplifying the differential signal, and generating a first non-inverted signal and a first inverted signal being inverted the first non-inverted signal;
a first inverter for generating a second non-inverted signal being inverted the first inverted signal; and
an interpolation unit for interpolating a phase difference between the first non-inverted signal and the second non-inverted signal,
wherein the interpolation circuit comprises:
a first interpolation inverter for inverting the first non-inverted signal;
a second interpolation inverter for inverting the second non-inverted signal;
a third interpolation inverter for inverting depending on a charge/discharge of the capacitor; and
a capacitor for charging/discharging depending on an output signal from the first and the second interpolation inverters.
2. The signal conversion circuit according to claim 1 , wherein the differential amplifier circuit comprises:
a first differential pair for generating the first non-inverted signal; and
a second differential pair for generating the first inverted signal.
3. The signal conversion circuit according to claim 2 , wherein the first and the second differential pairs comprise:
a first transistor inputted one signal of the differential signal to a control terminal;
a second transistor connected in series to the first transistor;
a third transistor inputted another signal of the differential signal to a control terminal; and
a fourth transistor connected in series to the third transistor to form a current mirror with the second transistor,
wherein the first non-inverted signal or the first inverted signal is outputted from an intermediate node between the third transistor and the fourth transistor.
4. The signal conversion circuit according to claim 1 , wherein the differential amplifier circuit comprises a differential pair for outputting the first non-inverted signal from one output terminal and outputting the first inverted signal from another output terminal.
5. The signal conversion circuit according to claim 4 , wherein the differential amplifier circuit comprises two differential pair circuits, one differential pair circuit outputting a first non-inverted signal and a second differential pair circuit outputting a first inverted signal, and each differential pair circuit comprises:
a first transistor inputted one signal of the differential signal to a control terminal;
a second transistor connected in series to the first transistor;
a third transistor inputted another signal of the differential signal to a control terminal; and
a fourth transistor connected in series to the third transistor,
wherein an intermediate node between the first transistor and the second transistor of one differential pair circuit is connected to a control terminal of the fourth transistor in the differential pair circuit that outputs one of the first non-inverted signal or the first inverted signal, and
an intermediate node between the third transistor and the fourth transistor of the second differential pair is connected to a control terminal of the second transistor in the differential pair circuit that outputs the other of the first non-inverted signal and the first inverted signal.
6. The signal conversion circuit according to claim 1 , further comprising:
a first inverter group for inverting the first non-inverted signal for an even number of times and inputting the first non-inverted signal to the interpolation circuit; and
a second inverter group for inverting the first inverted signal for an even number of times and inputting the inverted signal to the first inverter.
7. A signal conversion circuit comprising:
a conversion unit for converting a differential signal being inputted into a first single-ended signal and a second single-ended signal, said first single-ended signal having a duty ratio larger by an error compared to a duty ratio of said inputted differential signal and a said second single-ended signal having a duty ratio smaller by an error compared to said duty ratio of said inputted differential signal; and
an interpolation unit for interpolating the first single-ended signal and the second single-ended signal.
8. The signal conversion circuit according to claim 7 , wherein the first and the second single-ended signals are non-inverted signals which are the amplified differential signal.
9. The signal conversion circuit according to claim 8 , wherein the conversion unit comprises:
a first inverter group for inverting the amplified differential signal for an even number of times and transferring the amplified differential signal as the first single-ended signal; and
a second inverter group for inverting the amplified differential signal for an odd number of times and transferring the amplified differential signal as the second single-ended signal.
10. The signal conversion circuit according to claim 8 , wherein the conversion unit comprises a first differential pair transistor for amplifying the differential signal and the first and the second single-ended signals are generated according to a differential signal amplified by the first differential pair transistor.
11. The signal conversion circuit according to claim 8 , wherein:
the conversion unit comprises a first and a second differential pair transistors for amplifying the differential signal;
the first single-ended signal is generated according to a signal that is a differential signal amplified by the first differential pair transistor; and
the second single-ended signal is generated according to a signal that is a differential signal amplified by the second differential pair transistor.
12. The signal conversion circuit according to claim 7 , wherein:
the interpolation unit sets a waveform that lies almost midway between a rising waveform of the first single-ended signal and a rising waveform of the second single-ended signal to be a rising waveform for an output signal, and
a waveform that lies almost midway between a falling waveform of the first single-ended signal and a falling waveform of the second single-ended signal to be a falling waveform for an output signal.
13. A signal conversion circuit for converting an inputted differential signal into a single-ended signal, comprising:
a differential amplifier circuit for amplifying the differential signal, and generating a first non-inverted signal and a first inverted signal being inverted the first non-inverted signal;
a first inverter for generating a second non-inverted signal being inverted the first inverted signal; and
an interpolation unit for interpolating a phase difference between the first non-inverted signal and the second non-inverted signal, wherein the interpolation circuit comprises:
a first and a second interpolation transistors for inputting the first non-inverted signal to a control terminal;
a third and a fourth interpolation transistors for inputting the second non-inverted signal to a control terminal;
a first parallel circuit including the first interpolation transistor and the third interpolation transistor connected in parallel to the first transistor;
a second parallel circuit including the second interpolation transistor and the fourth interpolation transistor connected in parallel to the second transistor, and connected in series with the first parallel circuit; and
a capacitor connected to an intermediate node between the first parallel circuit and the second parallel circuit.