Systems and methods for discharging an AC input capacitor with automatic detection

A system for discharging a capacitor, the system comprising:

• a signal detector configured to receive an input signal and generate a detection signal based on at least information associated with the input signal, the input signal being associated with an alternate current signal received by a capacitor including a first capacitor terminal and a second capacitor terminal;
• and
• a discharge control component configured to receive at least the detection signal and generate an output signal to discharge the capacitor if the detection signal satisfies one or more conditions;
• wherein the discharge control component is further configured to generate the output signal to discharge the capacitor if the detection signal indicates that, during a predetermined time period, the input signal decreases monotonically, the predetermined time period being longer than half a period of the alternate current signal.

A system for discharging a capacitor, the system comprising:

• a signal detector configured to receive an input signal and generate a detection signal based on at least information associated with the input signal, the input signal being associated with an alternate current signal received by a capacitor including a first capacitor terminal and a second capacitor terminal;
• and
• a discharge control component configured to receive at least the detection signal and generate an output signal to discharge the capacitor if the detection signal satisfies one or more conditions;
• wherein the discharge control component is further configured to generate the output signal to discharge the capacitor if the detection signal indicates that, during a predetermined time period, the input signal increases monotonically, the predetermined time period being longer than half a period of the alternate current signal.

A system for discharging a device, the system comprising:

• a first transistor including a first transistor terminal, a second transistor terminal and a third transistor terminal;
• a second transistor including a fourth transistor terminal, a fifth transistor terminal and a sixth transistor terminal;
• a third transistor including a seventh transistor terminal, an eighth transistor terminal and a ninth transistor terminal;
• and
• a fourth transistor including a tenth transistor terminal, an eleventh transistor terminal and a twelfth transistor terminal;
• wherein:
• the second transistor terminal is connected to the fourth transistor terminal;
• the fifth transistor terminal is connected to the seventh transistor terminal;
• and
• the eighth transistor terminal is connected to the eleventh terminal and configured to receive an input signal;
• wherein the system is further configured to, if the input signal satisfies one or more conditions,
• turn on the first transistor and the fourth transistor;
• and
• discharge the device through at least the first transistor and the fourth transistor.

A system for detecting an input signal and discharging a device, the system comprising:

• a first transistor including a first transistor terminal, a second transistor terminal and a third transistor terminal;
• a second transistor including a fourth transistor terminal, a fifth transistor terminal and a sixth transistor terminal;
• a third transistor including a seventh transistor terminal, an eighth transistor terminal and a ninth transistor terminal;
• a first resistor including a first resistor terminal and a second resistor terminal;
• and
• a second resistor including a third resistor terminal and a fourth resistor terminal;
• wherein:
• the third transistor terminal is connected, directly or indirectly, to the fourth transistor terminal;
• the third transistor terminal is connected, directly or indirectly, to the first resistor terminal;
• the second resistor terminal is connected to the third resistor terminal;
• and
• the fourth resistor terminal is connected to the seventh transistor terminal;
• wherein:
• the first transistor terminal is configured to receive an input signal;
• the second transistor terminal is configured to receive a first drive signal;
• the fifth transistor terminal is configured to receive a second drive signal;
• and
• the eighth transistor terminal is configured to receive a third drive signal;
• wherein the system is further configured to, if the first drive signal satisfies one or more first conditions and the second drive signal satisfies one or more second conditions,
• turn on the first transistor and the second transistor;
• and
• discharge the device through at least the first transistor and the second transistor;
• wherein the system is further configured to, if the first drive signal satisfies the one or more first conditions and the third drive signal satisfies one or more third conditions,
• turn on the first transistor and the third transistor;
• and
• generate an output signal based on at least information associated with the input signal.