Systems and methods for driving a bipolar junction transistor by adjusting base current with time

A method for driving a bipolar junction transistor for a power converter, the method comprising:

• generating a drive current signal;
• and
• outputting the drive current signal to the bipolar junction transistor to adjust a primary current flowing through a primary winding of the power converter;
• wherein:
• the process for outputting the drive current signal to the bipolar junction transistor includes driving the bipolar junction transistor to operate in a hard-saturation region during a first time period and a second time period;
• and
• the process for driving the bipolar junction transistor to operate in the hard-saturation region during the first time period and the second time period includes:
• receiving a feedback signal associated with the primary current;
• and
• generating the drive current signal based on at least information associated with the feedback signal during at least the second time period;
• wherein:
• the first time period is followed by the second time period;
• the first time period starts at a first time and ends at a second time;
• the second time period starts at a third time and ends at a fourth time;
• the drive current signal is equal to a first current at the first time;
• the drive current signal is equal to a second current at the second time;
• the drive current signal is equal to a third current at the third time;
• and
• the drive current signal is equal to a fourth current at the fourth time;
• wherein:
• the second current is larger than the third current in magnitude;
• and
• the second time and the third time are the same;
• wherein the fourth current is larger than the third current in magnitude.

A system for driving a bipolar junction transistor for a power converter, the system comprising:

• a current generator configured to output a drive current signal to the bipolar junction transistor to adjust a primary current flowing through a primary winding of the power converter;
• wherein the current generator is further configured to:
• output the drive current signal to turn on the bipolar junction transistor during a first time period and a second time period, the first time period being followed by the second time period;
• drive the bipolar junction transistor to operate in a hard-saturation region during the first time period;
• and
• drive the bipolar junction transistor to operate in a quasi-saturation region during the second time period;
• wherein:
• the first time period starts at a first time and ends at a second time;
• and
• the second time period starts at a third time and ends at a fourth time;
• wherein:
• the drive current signal is equal to a first current at the first time;
• the drive current signal is equal to a second current at the second time;
• the drive current signal is equal to a third current at the third time;
• and
• the drive current signal is equal to a fourth current at the fourth time;
• wherein the current generator is further configured to:
• receive a feedback signal associated with the primary current;
• and
• generate the drive current signal based on at least information associated with the feedback signal during at least the first time period;
• wherein:
• the second current is larger than the third current in magnitude;
• and
• the second time and the third time are the same;
• wherein the second current is larger than the first current in magnitude;
• wherein:
• the current generator is further configured to output the drive current signal to turn off the bipolar junction transistor during a third time period after the second time period;
• the third time period starts at a fifth time;
• the drive current signal is equal to a fifth current at the fifth time;
• and
• the fifth current is different from the fourth current;
• wherein:
• the fourth current is configured to flow into the bipolar junction transistor;
• and
• the fifth current is configured to flow out of the bipolar junction transistor.

A method for driving a bipolar junction transistor for a power converter, the method comprising:

• generating a drive current signal;
• and
• outputting the drive current signal to the bipolar junction transistor to adjust a primary current flowing through a primary winding of the power converter;
• wherein:
• the process for outputting the drive current signal to the bipolar junction transistor includes outputting the drive current signal to turn on the bipolar junction transistor during a first time period and a second time period;
• the process for outputting the drive current signal to turn on the bipolar junction transistor during the first time period and the second time period includes:
• driving the bipolar junction transistor to operate in a hard-saturation region during the first time period;
• and
• driving the bipolar junction transistor to operate in a quasi-saturation region during the second time period;
• wherein:
• the first time period is followed by the second time period;
• the first time period starts at a first time and ends at a second time;
• the second time period starts at a third time and ends at a fourth time;
• the drive current signal is equal to a first current at the first time;
• the drive current signal is equal to a second current at the second time;
• the drive current signal is equal to a third current at the third time;
• and
• the drive current signal is equal to a fourth current at the fourth time;
• wherein:
• the second current is larger than the third current in magnitude;
• and
• the second time and the third time are the same;
• wherein the second current is larger than the first current in magnitude;
• wherein:
• the outputting the drive current signal to the bipolar junction transistor to adjust a primary current flowing through a primary winding of the power converter includes outputting the drive current signal to turn off the bipolar junction transistor during a third time period after the second time period;
• the third time period starts at a fifth time;
• the drive current signal is equal to a fifth current at the fifth time;
• and
• the fifth current is different from the fourth current;
• wherein:
• the fourth current is configured to flow into the bipolar junction transistor;
• and
• the fifth current is configured to flow out of the bipolar junction transistor.

A system for driving a bipolar junction transistor for a power converter, the system comprising:

• a current generator configured to output a drive current signal to the bipolar junction transistor to adjust a primary current flowing through a primary winding of the power converter;
• wherein the current generator is further configured to:
• output the drive current signal to turn on the bipolar junction transistor during a first time period and a second time period and to turn off the bipolar junction transistor during a third time period and a fourth time period;
• drive the bipolar junction transistor to operate in a hard-saturation region during the first time period;
• and
• drive the bipolar junction transistor to operate in a quasi-saturation region during the second time period;
• wherein:
• the first time period is followed by the second time period;
• the second time period is followed by the fourth time period;
• and
• the first time period is preceded by the third time period;
• wherein:
• the first time period starts at a first time and ends at a second time;
• the second time period starts at a third time and ends at a fourth time;
• the third time period ends at a fifth time;
• and
• the fourth time period starts at a sixth time;
• wherein:
• the drive current signal is equal to a first current at the first time;
• the drive current signal is equal to a second current at the second time;
• the drive current signal is equal to a third current at the third time;
• the drive current signal is equal to a fourth current at the fourth time;
• the drive current signal is equal to a fifth current at the fifth time;
• and
• the drive current signal is equal to a sixth current at the sixth time;
• wherein:
• the second current is larger than the third current in magnitude;
• the fifth current is smaller than the first current in magnitude;
• and
• the sixth current is different from the fourth current.

A method for driving a bipolar junction transistor for a power converter, the method comprising:

• generating a drive current signal;
• and
• outputting the drive current signal to the bipolar junction transistor to adjust a primary current flowing through a primary winding of the power converter;
• wherein the process for outputting the drive current signal to the bipolar junction transistor includes:
• outputting the drive current signal to turn on the bipolar junction transistor during a first time period and a second time period;
• and
• outputting the drive current signal to turn off the bipolar junction transistor during a third time period and a fourth time period;
• wherein the process for outputting the drive current signal to turn on the bipolar junction transistor during the first time period and the second time period includes:
• driving the bipolar junction transistor to operate in a hard-saturation region during the first time period;
• and
• driving the bipolar junction transistor to operate in a quasi-saturation region during the second time period;
• wherein:
• the first time period is followed by the second time period;
• the second time period is followed by the fourth time period;
• and
• the first time period is preceded by the third time period;
• wherein:
• the first time period starts at a first time and ends at a second time;
• the second time period starts at a third time and ends at a fourth time;
• the third time period ends at a fifth time;
• and
• the fourth time period starts at a sixth time;
• wherein:
• the drive current signal is equal to a first current at the first time;
• the drive current signal is equal to a second current at the second time;
• the drive current signal is equal to a third current at the third time;
• the drive current signal is equal to a fourth current at the fourth time;
• the drive current signal is equal to a fifth current at the fifth time;
• and
• the drive current signal is equal to a sixth current at the sixth time;
• wherein:
• the second current is larger than the third current in magnitude;
• the fifth current is smaller than the first current in magnitude;
• and
• the sixth current is different from the fourth current.

A system for driving a bipolar junction transistor for a power converter, the system comprising:

• a current generator configured to output a drive current signal to a bipolar junction transistor to adjust an output current flowing through a primary winding of a power converter;
• wherein the current generator is further configured to:
• output the drive current signal to turn on the bipolar junction transistor during a first time period, a second time period, and a third time period, the second time period separating the first time period from the third time period;
• drive the bipolar junction transistor to operate in a first mode during the first time period and the second time period;
• and
• drive the bipolar junction transistor to operate in a second mode during the third time period;
• wherein:
• the first time period starts at a first time and ends at a second time;
• the second time period starts at a third time and ends at a fourth time;
• and
• the third time period starts at a fifth time and ends at a sixth time;
• wherein:
• the drive current signal is equal to a first current at the first time;
• the drive current signal is equal to a second current at the second time;
• the drive current signal is equal to a third current at the third time;
• the drive current signal is equal to a fourth current at the fourth time;
• the drive current signal is equal to a fifth current at the fifth time;
• and
• the drive current signal is equal to a sixth current at the sixth time;
• wherein:
• the second current is larger than the third current in magnitude;
• and
• the fourth current is larger than the fifth current in magnitude.

A method for driving a bipolar junction transistor for a power converter, the method comprising:

• generating a drive current signal;
• and
• outputting the drive current signal to a bipolar junction transistor to adjust an output current flowing through a primary winding of a power converter;
• wherein the outputting the drive current signal to the bipolar junction transistor includes:
• outputting the drive current signal to turn on the bipolar junction transistor during a first time period, a second time period, and a third time period, the second time period separating the first time period from the third time period;
• driving the bipolar junction transistor to operate in a first mode during the first time period and the second time period;
• and
• driving the bipolar junction transistor to operate in a second mode during the third time period;
• wherein:
• the first time period starts at a first time and ends at a second time;
• the second time period starts at a third time and ends at a fourth time;
• and
• the third time period starts at a fifth time and ends at a sixth time;
• wherein:
• the drive current signal is equal to a first current at the first time;
• the drive current signal is equal to a second current at the second time;
• the drive current signal is equal to a third current at the third time;
• the drive current signal is equal to a fourth current at the fourth time;
• the drive current signal is equal to a fifth current at the fifth time;
• and
• the drive current signal is equal to a sixth current at the sixth time;
• wherein:
• the second current is larger than the third current in magnitude;
• and
• the fourth current is larger than the fifth current in magnitude.