Power amplifier clipping circuit for minimizing output distortion
First Claim
1. A power amplifier clipping circuit comprising:
- an input voltage level dividing unit which generates a first dividing voltage and a second dividing voltage that divide an interval to which the level of an input voltage belongs;
a first bias transistor and a second bias transistor which are connected to a positive internal power source voltage, the first and second bias transistors forming a current mirror and providing a bias voltage to a predetermined first differential amplifying unit;
a third bias transistor which is connected to the first bias transistor and provides a bias voltage to the first differential amplifying unit;
a first constant current source which is connected to the third bias transistor and a negative internal power source voltage, and controls the third bias transistor;
the first differential amplifying unit which receives the first dividing voltage and the input voltage, and if the level of the input voltage is between the first dividing voltage and a predetermined first clipping voltage, generates a first output signal, while if the level of the input voltage exceeds the first dividing voltage, generates a second output signal;
a fourth bias transistor and a fifth bias transistor which are connected to a negative internal power source voltage, the fourth and fifth bias transistors forming a current mirror, and providing a bias voltage to a predetermined second differential amplifying unit;
a sixth bias transistor which is connected to the fourth bias transistor and provides a bias voltage to the second differential amplifying unit;
a second constant current source which is connected to the sixth bias transistor and a positive internal power source voltage, and controls the sixth bias transistor;
the second differential amplifying unit which receives the second dividing voltage and the input voltage, and if the level of the input voltage is between a predetermined second clipping voltage and the second dividing voltage, generates a third output signal, while if the level of the input voltage exceeds the second dividing voltage, generates a fourth output signal;
a first output voltage control unit which is connected between the negative internal power source voltage and an output node in which an input resistor that is serially connected to the input voltage is connected to a power amplifier, and in response to the first and second output signals, lowers the level of the input voltage and provides the input voltage to the power amplifier; and
a second output voltage control unit which is connected between the positive internal power source voltage and the output node, and in response to the third and the fourth output signal, raises the level of the input voltage and provides the input voltage to the power amplifier.
1 Assignment
0 Petitions
Accused Products
Abstract
A power amplifier clipping circuit prevents sudden output changes when clipped from excessive input voltage, and includes an input voltage divider, two bias transistors connected to a positive voltage source, a third bias transistor connected to the first bias transistor and a first differential amplifier, a first current source connected to the third bias transistor and a negative voltage source and the first differential amplifier, fourth and fifth bias transistors connected to a negative voltage source and a second differential amplifier, a sixth bias transistor connected to the fourth bias transistor and the second differential amplifier, a second current source connected to the sixth bias transistor and a positive voltage source, a first output voltage controller connected between the negative voltage source and an output with a serial input resistor, and a second output voltage controller connected between the positive voltage source and the output and power amplifier.
-
Citations
20 Claims
-
1. A power amplifier clipping circuit comprising:
-
an input voltage level dividing unit which generates a first dividing voltage and a second dividing voltage that divide an interval to which the level of an input voltage belongs;
a first bias transistor and a second bias transistor which are connected to a positive internal power source voltage, the first and second bias transistors forming a current mirror and providing a bias voltage to a predetermined first differential amplifying unit;
a third bias transistor which is connected to the first bias transistor and provides a bias voltage to the first differential amplifying unit;
a first constant current source which is connected to the third bias transistor and a negative internal power source voltage, and controls the third bias transistor;
the first differential amplifying unit which receives the first dividing voltage and the input voltage, and if the level of the input voltage is between the first dividing voltage and a predetermined first clipping voltage, generates a first output signal, while if the level of the input voltage exceeds the first dividing voltage, generates a second output signal;
a fourth bias transistor and a fifth bias transistor which are connected to a negative internal power source voltage, the fourth and fifth bias transistors forming a current mirror, and providing a bias voltage to a predetermined second differential amplifying unit;
a sixth bias transistor which is connected to the fourth bias transistor and provides a bias voltage to the second differential amplifying unit;
a second constant current source which is connected to the sixth bias transistor and a positive internal power source voltage, and controls the sixth bias transistor;
the second differential amplifying unit which receives the second dividing voltage and the input voltage, and if the level of the input voltage is between a predetermined second clipping voltage and the second dividing voltage, generates a third output signal, while if the level of the input voltage exceeds the second dividing voltage, generates a fourth output signal;
a first output voltage control unit which is connected between the negative internal power source voltage and an output node in which an input resistor that is serially connected to the input voltage is connected to a power amplifier, and in response to the first and second output signals, lowers the level of the input voltage and provides the input voltage to the power amplifier; and
a second output voltage control unit which is connected between the positive internal power source voltage and the output node, and in response to the third and the fourth output signal, raises the level of the input voltage and provides the input voltage to the power amplifier. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
-
-
17. A method for clipping a power amplifier output, the method comprising:
-
receiving an input voltage;
generating first and second dividing voltages that divide an interval of the input voltage;
comparing the input voltage with the first dividing voltage and with a predetermined first clipping voltage;
generating a first output signal if the level of the input voltage is between the first dividing voltage and the first clipping voltage;
generating a second output signal if the level of the input voltage exceeds the first dividing voltage;
comparing the input voltage with the second dividing voltage and with a predetermined second clipping voltage;
generating a third output signal if the level of the input voltage is between the second clipping voltage and the second dividing voltage;
generating a fourth output signal if the level of the input voltage exceeds the second dividing voltage;
adjusting downward the level of the input voltage in response to the first and second output signals;
adjusting upward the level of the input voltage in response to the third and fourth output signals; and
providing the adjusted input voltage to the power amplifier. - View Dependent Claims (18)
-
-
19. A clipping circuit for a power amplifier, the clipping circuit comprising:
-
receiver means for receiving an input voltage;
divider means for generating first and second dividing voltages that divide an interval of the input voltage;
first comparator means for comparing the input voltage with the first dividing voltage and with a predetermined first clipping voltage;
first generator means for generating a first output signal if the level of the input voltage is between the first dividing voltage and the first clipping voltage;
second generator means for generating a second output signal if the level of the input voltage exceeds the first dividing voltage;
second comparator means for comparing the input voltage with the second dividing voltage and with a predetermined second clipping voltage;
third generator means for generating a third output signal if the level of the input voltage is between the second clipping voltage and the second dividing voltage;
fourth generator means for generating a fourth output signal if the level of the input voltage exceeds the second dividing voltage;
first adjuster means for adjusting downward the level of the input voltage in response to the first and second output signals;
second adjuster means for adjusting upward the level of the input voltage in response to the third and fourth output signals; and
provider means for providing the adjusted input voltage to the power amplifier. - View Dependent Claims (20)
-
Specification