LED tube lamp with improved compatibility with an electrical ballast

摘要

A light emitting diode (LED) tube lamp includes a lamp tube; a first external connection terminal coupled to the lamp tube and for receiving an external driving signal; a second external connection terminal coupled to the lamp tube and for receiving an external driving signal; a first rectifier coupled to the first external connection terminal and configured to rectify the external driving signal to produce a rectified signal; a second rectifier coupled to the second external connection terminal for rectifying the external driving signal; a filtering circuit coupled to the first rectifier and the second rectifier and configured to filter the rectified signal to produce a filtered signal; an LED lighting module coupled to the filtering circuit and configured to receive the filtered signal for emitting light; and a first bypass circuit coupled between the first rectifying circuit and the second external connection terminal. The first external connection terminal is an input terminal for the first rectifier and a first node is directly electrically connected to an output terminal for the first rectifier. In addition, the second external connection terminal is an input terminal for the second rectifier and a second node is directly electrically connected to an output terminal for the second rectifier. Further the first bypass circuit includes a first terminal connected to second external connection terminal and a second terminal connected to the first node, and the first bypass circuit is configured such that when the external driving signal is initially input between the first external connection terminal and the second external connection terminal, the first bypass circuit initially conducts current bypassing the LED lighting module to prevent the LED tube lamp from emitting light, until the bypass circuit enters an open-circuit state, allowing a current to flow through the LED lighting module and thereby allowing the LED tube lamp to emit light.

主权项

1. A light emitting diode (LED) tube lamp, comprising:
a lamp tube; a first external connection terminal coupled to the lamp tube and for receiving an external driving signal; a second external connection terminal coupled to the lamp tube and for receiving an external driving signal; a first rectifying circuit coupled to the first external connection terminal and configured to rectify the external driving signal to produce a rectified signal; a second rectifying circuit coupled to the second external connection terminal for rectifying the external driving signal; a filtering circuit coupled to the first rectifying circuit and the second rectifying circuit, and configured to filter the rectified signal to produce a filtered signal; an LED lighting module coupled to the filtering circuit and configured to receive the filtered signal for emitting light; and a first ballast interface circuit coupled between the first rectifying circuit and the second external connection terminal, wherein the first ballast interface circuit is configured such that when the external driving signal is initially input between the first external connection terminal and the second external connection terminal, the first ballast interface circuit initially conducts current bypassing the LED lighting module to prevent the LED tube lamp from emitting light, until the ballast interface circuit enters an open-circuit state, allowing a current input at the first external connection terminal and second external connection terminal to flow through the LED lighting module and thereby allowing the LED tube lamp to emit light.