Abstract: An input clock buffer, comprising: a first capacitor; a second capacitor; a first amplifier, configured to generate a first output signal, comprising input terminals coupled to the first capacitor and the second capacitor, wherein the first capacitor and the second capacitor receives a differential input signal; a second amplifier, configured to generate a second output signal according to the differential input signal; a frequency detection circuit, configured to generate a frequency detection signal according to a frequency of the differential input signal; and a switch, located between an output of the first amplifier and an output of the second amplifier, configured to turn on and turn off according to the frequency detection signal.

Abstract: An input clock buffer, comprising: a first capacitor; a second capacitor; a first amplifier, configured to generate a first output signal, comprising input terminals coupled to the first capacitor and the second capacitor, wherein the first capacitor and the second capacitor receives a differential input signal; a second amplifier, configured to generate a second output signal according to the differential input signal; a frequency detection circuit, configured to generate a frequency detection signal according to a frequency of the differential input signal; and a switch, located between an output of the first amplifier and an output of the second amplifier, configured to turn on and turn off according to the frequency detection signal.

Abstract: A digital buffer device with self-calibration includes a first buffer circuit, detection circuit, and calibration circuit. The first buffer circuit has a buffer input terminal for receiving an input signal and a buffer output terminal as output of the digital buffer device. The detection circuit includes at least one second buffer circuit for receiving at least one reference signal and generating at least one detection signal to indicate circuit characteristic variations of the at least one second buffer circuit. The at least one second buffer circuit is of a same type of buffer as the first buffer circuit. The calibration circuit has a calibration input terminal for receiving the input signal, and a calibration output terminal coupled to the buffer output terminal. The calibration circuit is for calibrating the first buffer circuit to generate an output signal according to the input signal and the at least one detection signal.

Abstract: A digital buffer device with self-calibration includes a first buffer circuit, detection circuit, and calibration circuit. The first buffer circuit has a buffer input terminal for receiving an input signal and a buffer output terminal as output of the digital buffer device. The detection circuit includes at least one second buffer circuit for receiving at least one reference signal and generating at least one detection signal to indicate circuit characteristic variations of the at least one second buffer circuit. The at least one second buffer circuit is of a same type of buffer as the first buffer circuit. The calibration circuit has a calibration input terminal for receiving the input signal, and a calibration output terminal coupled to the buffer output terminal. The calibration circuit is for calibrating the first buffer circuit to generate an output signal according to the input signal and the at least one detection signal.

Abstract: An amplifier with an input stage comprising: a first current mirror; a first input differential pair; a first current source; a second current source; a second input differential pair, wherein the first input differential pair and the second input differential pair receive a reference voltage; a second current mirror; and a voltage control transmission circuit. An extra current path in the first current mirror is formed and a current flowing through the extra current path flows through the second current mirror to a ground when the reference voltage is higher than a first predetermined value. Also, an extra current path in the second current mirror is formed and a current flowing through the extra current path in the second current mirror flows to the first current mirror when the reference voltage is lower than a second predetermined value.

Abstract: An amplifier with an input stage comprising: a first current mirror; a first input differential pair; a first current source; a second current source; a second input differential pair, wherein the first input differential pair and the second input differential pair receive a reference voltage; a second current mirror; and a voltage control transmission circuit. An extra current path in the first current mirror is formed and a current flowing through the extra current path flows through the second current mirror to a ground when the reference voltage is higher than a first predetermined value. Also, an extra current path in the second current mirror is formed and a current flowing through the extra current path in the second current mirror flows to the first current mirror when the reference voltage is lower than a second predetermined value.

Abstract: A bandgap reference circuit incorporates first, second, and third current sources, an operational amplifier coupled to the second and the third current sources, a voltage divider, a first resistor, and first, second, and third bipolar transistors. The second bipolar transistor has a base configured to receive a bias voltage from the voltage divider. The third bipolar transistor has a base and a collector electrically connected to the ground voltage. The first resistor is coupled between the third current source and the third bipolar transistor.

Abstract: An exemplary embodiment of the present disclosure illustrates a duty cycle correction apparatus for fast adjusting internal clocks to have specific duty cycles. Firstly, a reference clock is adjusted to have one specific duty cycle in response to analog feedback clocks. Then, by using a phase detector, phases of the reference clock and one internal clock are compared to generate a phase detection signal. Next, by using a digital-analog converter, complementary signals are generated according to a phase detection signal received by the counter, and the signals are used to adjust the duty cycles of the internal clocks. When the complementary signals make the duty cycle of the internal clock equals to the specific duty cycle, codes of the complementary signals are recorded.

Abstract: A bandgap reference circuit incorporates first, second, and third current sources, an operational amplifier coupled to the second and the third current sources, a voltage divider, a first resistor, and first, second, and third bipolar transistors. The second bipolar transistor has a base configured to receive a first voltage from the voltage divider. The third bipolar transistor has a base configured to receive a second voltage from the voltage divider. The first resistor is coupled between the third current source and the third bipolar transistor.

Abstract: A duty cycle correction circuit comprises a duty cycle detector, a filter, a comparator, a SAR DAC, an equalization device, a pass gate circuit, and a duty cycle corrector. The duty cycle detector generates control signals in response to internal clock signals. The equalization device equalizes voltage levels of the control signals, and the pass gate circuit applies the control signals to the duty cycle corrector. The filter obtains average voltages of the control signals. The comparator compares output signals from the filter to generate a comparison result. The SAR DAC performs a SAR algorithm to generate analog output signals based on the comparison result. The duty cycle corrector receives external clock signals, the analog output signals, and output signals from the pass gate circuit to generate the internal clock signals with a corrected duty cycle.