Operational amplifier and integrating circuit
View Patent ↗An operational amplifier in accordance with one embodiment of the present invention includes a differential amplifier circuit to perform differential amplification of an input signal with respect to a reference potential Vbias, an output circuit to output a signal amplified by the differential amplifier circuit, a phase compensation capacitance connected between the output of the differential amplifier circuit and the output of the output circuit to compensate the phase of the signal output from the output circuit, and a diode connected in parallel with the phase compensation capacitance.
1. An operational amplifier, comprising:
a differential amplifier circuit to perform differential amplification of an input signal with respect to a reference potential;
an output circuit to output a signal amplified by the differential amplifier circuit;
a phase compensation resistor with one end connected to an output of the differential amplifier circuit;
a phase compensation capacitance connected between the other end of the phase compensation resistor and the output circuit, to compensate a phase of the signal output from the output circuit; and
a diode connected in a parallel manner with the phase compensation capacitance.
2. The operational amplifier according to claim 1 , wherein the phase compensation resistor has one end connected to the phase compensation capacitance and the diode and the other end connected to the differential amplifier circuit, the phase compensation capacitance and the diode being connected in parallel with each other.
3. The operational amplifier according to claim 1 , wherein:
the differential input of the differential amplifier circuit includes a P-channel MOSFET; and
an anode of the diode is connected to the differential amplifier circuit side of the phase compensation capacitance and a cathode of the diode is connected to the output circuit side of the phase compensation capacitance.
4. The operational amplifier according to claim 1 , wherein:
the differential input of the differential amplifier circuit includes an N-channel MOSFET; and
a cathode of the diode is connected to the differential amplifier circuit side of the phase compensation capacitance and an anode of the diode is connected to the output circuit side of the phase compensation capacitance.
5. The operational amplifier according to claim 1 , wherein the phase compensation resistor has one end connected to the phase compensation capacitance and the other end connected to the differential amplifier circuit and the diode.
6. The operational amplifier according to claim 5 , wherein:
the differential input of the differential amplifier circuit includes a P-channel MOSFET; and
an anode of the diode is connected to the differential amplifier circuit side of the phase compensation resistor and a cathode of the diode is connected to the output circuit side of the phase compensation capacitance.
7. The operational amplifier according to claim 5 , wherein:
the differential input of the differential amplifier circuit includes an N-channel MOSFET; and
a cathode of the diode is connected to the differential amplifier circuit side of the phase compensation resistor and an anode of the diode is connected to the output circuit side of the phase compensation capacitance.
8. An integrating circuit, comprising:
an operational amplifier;
an integrating capacitance connected in parallel with the operational amplifier; and
a reset switch connected in parallel with the integrating capacitance;
wherein the operational amplifier includes:
a differential amplifier circuit to perform differential amplification of an input signal with respect to a reference potential;
an output circuit to output a signal amplified by the differential amplifier circuit;
a phase compensation capacitance connected between the differential amplifier circuit and the output circuit to compensate a phase of the signal output from the output circuit; and
a diode connected in a parallel manner with the phase compensation capacitance.
9. The integrating circuit according to claim 8 , further comprising a phase compensation resistor having one end connected to the phase compensation capacitance and the diode and the other end connected to the differential amplifier circuit, the phase compensation capacitance and the diode being connected in parallel with each other.
10. The integrating circuit according to claim 8 , wherein:
the differential input of the differential amplifier circuit includes a P-channel MOSFET; and
an anode of the diode is connected to the differential amplifier circuit side of the phase compensation capacitance and a cathode of the diode is connected to the output circuit side of the phase compensation capacitance.
11. The integrating circuit according to claim 8 , wherein:
the differential input of the differential amplifier circuit includes an N-channel MOSFET; and
a cathode of the diode is connected to the differential amplifier circuit side of the phase compensation capacitance and an anode of the diode is connected to the output circuit side of the phase compensation capacitance.
12. The integrating circuit according to claim 8 , further comprising a phase compensation resistor having one end connected to the phase compensation capacitance and the other end connected to the differential amplifier circuit and the diode.
13. The integrating circuit according to claim 12 , wherein:
the differential input of the differential amplifier circuit includes a P-channel MOSFET; and
an anode of the diode is connected to the differential amplifier circuit side of the phase compensation resistor and a cathode of the diode is connected to the output circuit side of the phase compensation capacitance.
14. The integrating circuit according to claim 12 , wherein:
the differential input of the differential amplifier circuit includes an N-channel MOSFET; and
a cathode of the diode is connected to the differential amplifier circuit side of the phase compensation resistor and an anode of the diode is connected to the output circuit side of the phase compensation capacitance.
15. An operational amplifier, comprising:
a differential amplifier circuit to perform differential amplification of an input signal with respect to a reference potential;
an output circuit to output a signal amplified by the differential amplifier circuit;
a capacitor;
a resistor serially connected to the capacitor, thereby forming a serially-connected capacitor/resistor pair, wherein the serially-connected capacitor/resistor pair is connected between the differential amplifier circuit and the output circuit to compensate the phase of the signal output from the output circuit;
a diode connected in parallel with at least a portion of the serially-connected capacitor/resistor pair;
an integrating capacitance connected in parallel with the operational amplifier; and
a reset switch connected in parallel with the integrating capacitance.
16. The operational amplifier of claim 15 , wherein the diode is connected in parallel to the capacitor.
17. The operational amplifier of claim 15 , wherein the diode is connected in parallel to the serially-connected capacitor/resistor pair.
18. The operational amplifier according to claim 15 , wherein:
the differential input of the differential amplifier circuit includes a P-channel MOSFET, and
an anode of the diode is connected to the differential amplifier circuit side of the phase compensation capacitance and a cathode of the diode is connected to the output circuit side of the phase compensation capacitance.
19. The operational amplifier according to claim 15 , wherein:
the differential input of the differential amplifier circuit includes an N-channel MOSFET, and
a cathode of the diode is connected to the differential amplifier circuit side of the phase compensation capacitance and an anode of the diode is connected to the output circuit side of the phase compensation capacitance.