LED tube lamp with two operating modes compatible with electrical ballasts

A light emitting diode (LED) tube lamp configured to receive an external driving signal, comprising:

• an LED module for emitting light, the LED module comprising an LED unit comprising an LED;
• a rectifying circuit for rectifying the external driving signal to produce a rectified signal;
• a mode determination circuit configured to detect a state of a property of the rectified signal, for selectively determining on performing a first mode or a second mode of lighting according to the state of the property of the rectified signal, wherein the mode determination circuit is configured such that when the LED tube lamp performs the first mode of lighting, the mode determination circuit allows continual current to flow through the LED unit until the external driving signal is disconnected from the LED tube lamp;
• and when the LED tube lamp performs the second mode of lighting, the mode determination circuit regulates the continuity of current to flow through the LED unit;
• and
• a capacitor coupled in series with the LED, wherein an equivalent current-limiting capacitance of the capacitor is a value presenting low impedance to the received external driving signal and having substantially no current-limiting effect on current entering the LED unit.

A light emitting diode tube lamp, comprising:

• a lamp tube;
• a first external connection terminal and a second external connection terminal coupled to the lamp tube and for receiving an external driving signal from an electrical ballast;
• a rectifying circuit for rectifying the external driving signal to produce a rectified signal;
• a ballast interface circuit configured to detect a state of a property of the rectified signal, for selectively determining on performing a first mode or a second mode of lighting according to the state of the property of the rectified signal;
• an LED module for emitting light, the LED module comprising an LED unit comprising an LED;
• a filtering circuit connected in parallel with the LED unit;
• and
• a discharge device connected in parallel with the LED unit and for discharging when a voltage across the LED unit is larger than a threshold voltage;
• wherein the ballast interface circuit is configured such that when the LED tube lamp performs the first mode of lighting, the ballast interface circuit allows continual current to flow through the LED unit until the external driving signal is disconnected from the LED tube lamp;
• and when the LED tube lamp performs the second mode of lighting, the ballast interface circuit regulates the continuity of current to flow through the LED unit.