LED tube lamp

  • US 10,448,479 B2
  • Filed: 08/13/2018
  • Issued: 10/15/2019
  • Est. Priority Date: 04/14/2015
  • Status: Active Grant
First Claim
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1. A light emitting diode (LED) tube lamp, comprising:

  • a lamp tube;

    two external connection terminals coupled to the lamp tube;

    a first rectifying circuit comprising diodes and connected to the two external connection terminals, wherein the two external connection terminals are for receiving an external driving signal and the first rectifying circuit is for rectifying the input external driving signal to produce a rectified signal;

    an LED module comprising LEDs for emitting light, the LED module configured to be driven based on the rectified signal;

    a driving circuit coupled between the first rectifying circuit and the LED module, and configured to drive the LED module; and

    a delay-control circuit coupled to the first rectifying circuit and comprising a control circuit and a switch, wherein the delay-control circuit is configured to receive the rectified signal and the control circuit is configured to control current conduction or cutoff of the switch depending on a driving signal derived from the rectified signal and received by the control circuit,wherein when the external driving signal is a low frequency signal, the delay-control circuit is configured to cause the rectified signal to be used by the driving circuit for driving the LED module to emit light, depending on a property of the rectified signal, andwherein following a first pre-set delay period after the low frequency external driving signal is input, throughout a subsequent second time period, when the control circuit determines that a voltage level of the received rectified signal has remained lower than a determination level, the control circuit controls the switch to be in a cutoff state preventing the LED module from emitting light,wherein the delay-control circuit comprises a passive component string connected to the control circuit to provide an operation signal, and the first pre-set delay period is determined by an RC time constant of the passive component string, andwherein the operation signal is a continuous signal without processing by an active component.

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