Abstract: A biasing circuit and a voltage control oscillator thereof are provided. The biasing circuit comprises a compensation circuit, a delay circuit and a comparison circuit. In the biasing circuit, the compensation circuit compensates a first differential voltage that is generated by the delay circuit so as to stabilize an output of the biasing circuit operated by a low-current or low-frequency. The jitter of the clock frequency that the voltage control oscillator output can be reduced.

Abstract: A DC level wandering cancellation circuit is provided. The DC level wandering cancellation circuit comprises a low pass filter, for receiving an input voltage; a high pass filter coupled to the low pass filter; an amplifier coupled to the high pass filter for receiving a reference voltage and an output signal of the high pass filter; a comparator coupled to the amplifier for receiving an output signal of the amplifier to compare the reference voltage with the output signal of the amplifier; a resistor coupled between outputs of the high pass filter and the amplifier; a control logic coupled to the comparator for receiving a compared result from the comparator; and a switching means coupled between the high pass filter and the output of the amplifier. The switching means is turned on for a predetermined interval by the control logic according to the compared result.

Abstract: A current mirror circuit is provided. The circuit includes a resistor having a first terminal connected to a current source, a first transistor having a substrate electrode connected to a drain electrode thereof, a second transistor having a substrate electrode connected to the substrate electrode of the first transistor, a third transistor having a substrate electrode connected to the substrate electrode of the first transistor, and a fourth transistor having a drain electrode for providing an output current.

Abstract: A current mirror circuit is provided. The circuit includes a resistor having a first terminal connected to a current source, a first transistor having a substrate electrode connected to a drain electrode thereof, a second transistor having a substrate electrode connected to the substrate electrode of the first transistor, a third transistor having a substrate electrode connected to the substrate electrode of the first transistor, and a fourth transistor having a drain electrode for providing an output current.

Abstract: A stable current source circuit with a compensation circuit, comprising: a PMOS current mirror, connected to a power supply so as to output a stable current; an NMOS current mirror, connected to a third bipolar junction transistor and a fourth compensation resistor; a third bipolar junction transistor, the emitter of the third bipolar junction transistor connected to the NMOS current mirror and both of the base and the collector grounded; and a fourth compensation resistor, interconnected between the NMOS current mirror and the compensation circuit. Alternatively, a compensation capacitor can be added so as to obtain better stability.

Abstract: A stable current source circuit with a compensation circuit, comprising: a PMOS current mirror, connected to a power supply so as to output a stable current; an NMOS current mirror, connected to a third bipolar junction transistor and a fourth compensation resistor; a third bipolar junction transistor, the emitter of the third bipolar junction transistor connected to the NMOS current mirror and both of the base and the collector grounded; and a fourth compensation resistor, interconnected between the NMOS current mirror and the compensation circuit. Alternatively, a compensation capacitor can be added so as to obtain better stability.

Abstract: The present invention provides a control circuit with multiple power sources, which accepts an output signal from a comparator circuit. This control circuit with multiple power sources contains two components: one is a voltage transferring circuit, which connects to the comparator and accepts the first and the second input voltages to react the controls of respective output signals for generating the first voltage potential and the second voltage potential; another is an output circuit, which connects to the voltage transferring circuit to react the controls of the first voltage potential and the second voltage potential for deciding the correct output from the first input voltage or the second input voltage.