Amplifier device and power supply device

A power supply device comprising:

• an amplifier device;
• and
• a feedback circuit configured to return a feedback signal back to the amplifier device, the feedback signal being varied with an output signal of the amplifier device, wherein
• the amplifier device includes:
• a chopper amplifier having a pair of input terminals and an output terminal;
• a ripple attenuation loop;
• a low-pass filter connected to the output terminal of the chopper amplifier, the low-pass filter configured to receive the output signal from the chopper amplifier and output an output signal;
• and
• a buffer circuit configured to receive the output signal from the low-pass filter and output an output signal,
• the chopper amplifier includes:
• a first chopper circuit configured to chop a pair of input signals received from the pair of input terminals according to a first clock signal and output a pair of output signals;
• a first transconductance amplifier configured to receive the pair of output signals from the first chopper circuit and output a pair of differential output signals;
• a second chopper circuit configured to chop the pair of differential output signals received from the first transconductance amplifier according to the first clock signal and output a pair of output signals;
• and
• a converter configured to
• receive the pair of output signals from the second chopper circuit as differential input signals,
• convert the differential input signals to a single-ended signal, and
• output the single-ended signal,
• the ripple attenuation loop includes:
• a high-pass filter configured to receive the single-ended signal and output an output signal;
• a third chopper circuit configured to chop the output signal received from the high-pass filter and a reference voltage according to the first clock signal and output a pair of output signals;
• a fourth chopper circuit configured to chop the pair of output signals received from the third chopper circuit according to a second clock signal and output a pair of output signals, the second clock signal being different from the first clock signal;
• a second transconductance amplifier configured to receive the pair of output signals from the fourth chopper circuit and output a pair of differential output signals;
• a fifth chopper circuit having a pair of output terminals, the fifth chopper circuit configured to chop the pair of differential output signals received from the second transconductance amplifier according to the second clock signal and output a pair of output signals from the pair of output terminals;
• a first capacitor connected between the pair of output terminals of the fifth chopper circuit;
• and
• a third transconductance amplifier configured to receive the pair of output signals from the fifth chopper circuit and output a pair of differential output signals,
• the low-pass filter is configured to suppress ripple in the single-ended signal, and
• the pair of differential output signals of the third transconductance amplifier are coupled to the pair of differential output signals of the first transconductance amplifier, respectively.