초록 ▼

The embodiments of the present invention disclose a high power-supply rejection ratio (PSRR) amplifier circuit. The amplifier circuit comprises a low dropout regulator, a negative charge pump and an amplifier. The output voltages of the negative charge pump and the low dropout regulators don't track

The embodiments of the present invention disclose a high power-supply rejection ratio (PSRR) amplifier circuit. The amplifier circuit comprises a low dropout regulator, a negative charge pump and an amplifier. The output voltages of the negative charge pump and the low dropout regulators don't track the change of input voltage. Therefore the amplifier circuit has high PSRR.

대표청구항 ▼

1. An amplifier circuit, comprising: a regulator, coupled to a first input voltage, operable to generate a first output voltage;a negative charge pump, coupled to a first reference voltage and a second input voltage, operable to generate a second output voltage, wherein the negative charge pump comp

1. An amplifier circuit, comprising: a regulator, coupled to a first input voltage, operable to generate a first output voltage;a negative charge pump, coupled to a first reference voltage and a second input voltage, operable to generate a second output voltage, wherein the negative charge pump comprises a feedback loop, sampling the second output voltage and receiving the first reference voltage, configured to generate a regulating signal to regulate the second output voltage; andan amplifier, wherein the first output voltage is coupled to a positive power supply end of the amplifier, and wherein the second output voltage is coupled to a negative power supply end of the amplifier. 2. The amplifier circuit according to claim 1, further comprises a second amplifier, wherein the first output voltage is further coupled to a positive power supply end of the second amplifier, and wherein the second output voltage is further coupled to a negative power supply end of the second amplifier. 3. The amplifier circuit according to claim 1, wherein the first input voltage equals the second input voltage. 4. The amplifier circuit according to claim 1, wherein the first output voltage is positive and the second output voltage is negative, and wherein the absolute value of the first output voltage equals the absolute value of the second output voltage. 5. The amplifier circuit according to claim 1, wherein the negative charge pump further comprises: a first series-coupled switch pair, comprising a first switch and a second switch, wherein the first switch and the second switch have a common end, and wherein the first switch pair is coupled between an input voltage and a system ground;a second series-coupled switch pair, comprising a third switch and a fourth switch, wherein the third switch and the fourth switch have a common end, and wherein the second switch pair is coupled between an output end of the charge pump and the system ground;a first capacitor, coupled between the common end of the first switch pair and the common end of the second switch pair; anda second capacitor, coupled between the output end of the charge pump and the system ground. 6. The amplifier circuit according to claim 5, wherein the first switch is a P-type metal-oxide semiconductor field effect transistor, and wherein the second switch, the third switch and the fourth switch are N-type metal-oxide semiconductor field effect transistor. 7. The amplifier circuit according to claim 5, wherein the first switch, the second switch and the third switch are controlled by a first control signal, and wherein the fourth switch is controlled by a second control signal, and wherein the second control signal is a complementary signal of the first control signal. 8. The amplifier circuit according to claim 1, wherein the feedback loop comprises: a sampling circuit, having an input coupled to the output end of the charge pump, and having an output; andan error amplifier, having a positive input end, a negative input end and an output end, wherein the positive input end is coupled to the output end of the sampling circuit, wherein the negative input end is coupled to the second reference voltage, and wherein the output end is configured to provide the regulating signal. 9. The amplifier circuit according to claim 8, wherein the sampling circuit is a voltage divider comprising a first resistor and a second resistor, wherein the voltage divider is coupled between the output end of the charge pump and a second reference voltage, and wherein the common end of the first resistor and the second resistor comprises the output end of the sampling circuit. 10. A method for supplying power to an amplifier, comprising: generating a first output voltage from a first input voltage;generating a second output voltage from a second input voltage and a first reference voltage; andproviding the first output voltage to a positive power supply of an amplifier and providing the second output voltage to a negative power supply of the amplifier;wherein the second output voltage is regulated by deriving a sampled output voltage of the second output voltage to generate a regulating signal according to the sampled output voltage and the first reference voltage, andutilizing the regulating signal to regulate the second output voltage. 11. The method for supplying power to an amplifier according to claim 10, wherein the first input voltage equals the second input voltage, and wherein the absolute value of the first output voltage equals the absolute value of the second output voltage. 12. The method for supplying power to an amplifier according to claim 10, wherein the sampled output voltage is derived from the second output voltage and a second reference voltage. 13. The method for supplying power to an amplifier according to claim 10, wherein utilizing the regulating signal to regulate the second output voltage further comprises: turning on a first switch and a fourth switch to couple a first capacitor to the second input voltage;turning off the first switch and the fourth switch and turning on a second switch and a third switch to couple the first capacitor to a second capacitor; andregulating the on-state resistance of the second switch by the regulating signal;wherein the second capacitor provides the second output voltage.